The van, Louisiana license plates BIG BOY, cruised past the gates of the Federal Correctional Institute in Texarkana, Tex. (down a road a piece from the court hearing the Clarence Harmon case), late yesterday morning, and went on by. An hour and a half later, the vehicle returned, and dropped off a passenger.

"Billy Cannon's here?" a prison guard asked one of the photographers among the media massed near the entrance. "All right!"

And so Dr. Cannon, LSU's Heisman Trophy football ace of the late 1950s, began a minimum of almost two years (of a five-year sentence) in the minimum-security prison as convicted counterfeiter. He walked alone into the penitentiary building (the Longest Yard?) and will return to Baton Rouge, under guard, to testify at the Oct. 11 trial of four codefendants . . .

Zema Williams, the self-described "No. 1 Redskin fan" who dons Indian costume and cheers at the games, says he was attacked and beaten in two separate incidents at Sunday's game in Philadelphia.

Williams, 42, manager of a Northeast D.C. used car lot, said he suffered a fractured left knee and other injuries when set upon by three Eagles' fans, who took his $485 war bonnet, $275 moccasins, pants and spear.

During the game, he said, "They came down and hit me in back of the head, knocked me down and threw my war bonnet into the lower deck." Later, in the parking lot, he related, "They knocked me down and held me on the ground while one guy put his foot on my knee and tried to bend it backwards."

Williams (no official connection with the Redskins) has attended all home games since 1978.

"I'll be at the game Sunday with the Chiefs but I might be in a wheelchair," he said.