As Redskin coach George Allen lists his priorities - fewer mistakes, better team play, better running game and a stronger pass rush - for tonight's 8 p.m. game against the Kansas City Chiefs at RFK Stadium, Washington fans have some other questions as the result of the first two preseason games:

Will Mark Moseley's kicking leg regain its effectiveness?

Will No. 2 quarterback Joe Theismann began to show more consistency?

Can Gerard Williams get enough experience to successfully man the left cornerback postion if Pat Fischer does not return from a back injury?

Only the cornerback situation is a concern for Allen at this stage because of extenuating circumstances for Moseley and Theismann. Moseley has been hindered by a hip pointer, and a week ago Allen was more interested in finding out what No. 3 quarterback Brian Dowling could do than watching Thiesmann perform.

Before the team left training camp in Carlisle, Pa., yesterday, Allen said his starters would play at least a half against the Chiefs who, like the Redskins, are 1-1 in preseason play. A number of Washington starters, including quarterback Billy Kilmer, played a quarter each in the first two games.

The expected crowd of 35,000 probably will see wide receiver Charley Taylor, the NFL's all-time leading receiver, return to action for the first time since he suffered a shoulder separation in the 1976 exhibition opener. Allen said Taylor would play unless a sudden shower dampened the playing fields.

"It's time for me to test it," Taylor said. "This is approaching the halfway point of the preseason. This is the time you start bringing the group together that's going to be playing in that opener at New York. You couldn't pick a better place for me to test the shoulder. We're playing at home against a good team."

Allen said that ailing wide receiver Frank Grant (hamstring) and safety Jake Scott (stiff neck) were doubtful participants.

The team was scheduled to practice last night at RFK and Allen said he would not decide whether to play running back Mike Thomas until after that workout. Thomas, who gained 1,101 yards last season and is the team's basic outside threat, ran at full speed Monday after recovering from a hamstring injury.

Thomas does not want to rush his return and said he could be ready for the Sept. 18 regular-season opener against the New York Giants by playing in the final two preseason games.

While Thomas' relatively minor leg injury generated tons of publicity, Moseley has struggled the past two weeks without any fanfare. His kickoffs have been short and the Redskins bypassed at least one field-goal attempt within his normal range.

But he looked like the Moseley of old during special-teams drills Tuesday and reported that the leg felt much better and that he could take a full swing at the ball again.

Theismann, who was intercepted three times in a 10-for-26 passing effort against Miami, thought he threw the ball against the Dolphins as well as he did a week against Cleveland. He was the third and final quarterback used by Allen against Miami.

"I don't think training camp had gone downhill for me; it's gone uphill," said Theismann. "You have to take into consideration the circumstances you played under, everybody who is on the field with you. It's a situation whereby people learn not one man makes a football team, but it takes 11 men to make a team go."

However, Theismann took full responsibility for his first interception.

"Frankly, I went away from the read and tried to get a bigger play," he said. "This is what you chalk up to experience, and you've got to play to get it. The mistakes I made, I'm glad they happened in a preseason game and not in the regular season."

It was the third game of the 1976 regular season before Washington's current offensive line was aligned as it has been for the past eight days: Tim Stokes at left tackle, Ron Saul at left guard, Len Hauss at center, Terry Hermeling at right guard, George Starke at right tackle.

Stokes is not overly concerned that the running game has not come around. He said pass blocking at his stage of traning and that Washington's offensive line is geared to a running back like Thomas, who has yet to play.

"We need to come off the ball together more. But the running game always takes more time," said Stokes. "Running is more timing; we don't have the proper mesh yet; we've had a lot of people in and out. A 1,000-yard rusher like Mike adds a whole new dimension. It makes our job easier. I'm not knocking Calvin Hill, but our offensive line is geared for Mike. There are things we have to do differently for Calvin."

Meanwhile, Kansas City, which defeated the Pittsburgh Steelers Saturday night, comes into Washington as a team transformed from one of the league's most veteran units to one of the youngest in three years under coach Paul Wiggin.

Starting quarterback Mike Livingston played the entire game against the Steelers, but Wiggin said he will start backup Tony Adams tonight and may play him the entire game. Ed Podolak, the team's veteran running back, is out with a shoulder separation and rookie Tony Reed, No. 2 draft choice from Colorado, will start in his place.

Walter White, the former Maryland star, returns as the full-time tight end for the first time in his three-year procareer. Wiggin had been using White and Billy Masters as a shuttle to bring in plays. Now Wiggin will do that with either wide receivers or running backs.

Wiggin plans to play a number of running backs and linebackers. But the starting defensive line is likely to see the most action because it needs the work. Left end Whitney Paul, left tackle Willie Lee and right tackle Keith Simons are all second-year men.

The new collective bargaining agreement between the players and management calls for four days off per month starting with the first exhibition games. A few Redskins have grumbled they got only 16 hours off after each of the first two exhibitions. But Allen will likely give them Friday and Saturday off, after their third exhibition game in 11 days. . . Tonight's game will be telecast live in Harrisonburg, Richmond, Lynchburg and Norfolk. An edited tape will be shown here Saturday on WJLA-TV-7.