In his first act since signing a new four-year contract to coach and general manage of the Redskins. George Allen signed a free agent wide receiver and met with several unsigned players.

Allen signed veteran wide receiver Earl Thomas, older brother of running back Mike Thomas, and also said he will decide later this week about what to do with former first string defensive end Verlon Biggs.

Biggs, 34, was cut by the Redskins and Saints last year, but is now trying to make a comeback in Washington. He has been working out a Redskin Park every day since January, and said yesterday, "I know I can still play. I'd like it to be here, but nothing has been decided."

Allen said he did not want to invite Biggs to camp, only to cut him again later. Biggs plays right defensive end, the same spot Allen hopes to buttress with rookie Duncan McColl.

Other team sources say Allen probably will wait to see how McColl develops before signing Biggs, who had a serious knee operation in 1975.

The signing of Thomas gives the Redskins another savvy, veteran and well-traveled receiver. Originally drafted by the Cardinals in 1971, Thomas has also spent time in Houston, his team in 1976.

Thomas, 6-foot-3 and 215 pounds, was used mostly on special teams last year. He played in seven games for the Oilers and was released during the offseason. His most productive season was 1974, when he caught 34 passes, five for touchdowns, with the Cardinals.

Allen sported a deep tan from his recent two-week vacation in California, and was in good spirits yesterday, telling several Shriners in attendance at a press conference, "Seeing you guys makes me feel good. You remind me a little bit of the Over the Hill Gang."

He said he would play all his regulars and "go all out to win" the Aug. 18 game against the Kansas City Chiefs at RFK Stadium sponsored by the Almas Temple Shrine.

Allen said he had met with unsigned middle linebacker Harold McLinton and hoped to have most of the team's 15 unsigned players in the fold before heading to camp on Saturday.

He also issued a warning to rookie Reggie Haynes, the team's unsigned seventh-round draft pick, saying he would have a difficult time making the club if he did not soon come to terms.

Allen also insisted he had been on the phone constantly in California trying to make a trade but "as of right now, I don't think we'll make a trade."