Kilmer played RB early in his career with SF right?
Kilmer was the last single-wing tailback. UCLA. The 49ers invented the shotgun just to use Kilmer's running ability.
Historical note: the single-wing had a tailback about three steps behind the center, a fullback one step closer and behind left or right guard, depending. Then a quarterback, who was a blocker, right behind the tackle on whichever side the fullback took. Plus a wingback one step back from the line and one step out from the end. Play started with a long snap to the tailback or, sometimes, the fullback.
Sammy Baugh was a tailback in his first seasons. I don't think the Redskins adopted the T-formation until about 1942. UCLA and Tenn. were about the last two major colleges to play the single wing.