In their final tuneup before the start of the 1985-86 NBA season, the Washington Bullets lost to the Philadelphia 76ers tonight, 103-102, before 10,716 at the Richmond Coliseum. The Sixers' winning margin was provided by Charles Barkley's free throw with three seconds remaining in the game.

The game was a curious, often uninspired affair, at least until the final six minutes. It was then that it became something more than an exhibition for Matt Guokas, Philadelphia's first-year coach, who inserted starters Barkley and Clemon Johnson, along with guard Sedale Threatt.

The score at the time was 88-84, Washington, a margin forged on the play of subsititutes Tom Sewell, Perry Moss, Tony Costner, Guy Williams and veteran Tom McMillen. Bullets Coach Gene Shue chose not to respond to Guokas' move and almost was rewarded with an inspiring victory. The Bullets just missed pulling out a win when a long-distance, last-second shot by Sewell carried over the rim.

"I think this was a new experience for Matty, being a new head coach," said Shue. "I think he sensed that his team had a chance to win the game, and he went for it."

Philadelphia rookie Terry Catledge was the game's high scorer with 19 points, and the Bullets were led by Cliff Robinson with 16.

The finish perked up what quickly had become a lethargic game. A number of players were missing: Moses Malone, Andrew Toney and Bobby Jones for Philadelphia and Dan Roundfield and Frank Johnson for the Bullets. That made it harder to glean a sense of comparison between the two squads, which appear to be the main challengers to supplant Boston atop the NBA's Atlantic Division.

"I thought the young players did very well, playing the whole fourth quarter like they did," said Shue. "The whole exhibition season was a very good one for us. We've got a lot of hard decisions to make."

The coach said those decisions probably would not be made until the last possible moment, most likely sometime on Thursday, before the team travels to Atlanta for the first game of the regular season Friday.

The Bullets have played the entire exhibition season without Roundfield -- who is hampered by a broken bone in his left arm -- and Johnson, who is recovering from a broken foot. General Manager Bob Ferry said tonight that he did not expect Roundfield -- due back within a week -- to go on the injured list.

Johnson is another story, though. The guard is expected to be out two more weeks, which would make his inclusion on the injured list almost a formality. Ferry said that decision will be made soon.

That move would free a spot on the roster for a guard, either Sewell or Moss. Both have played well throughout the exhibition season, Sewell on offense and Moss defensively. The difference could be only that Moss plays the point, the same position as Johnson.