It's just a 1 1/2" long piece of 3/4" angle iron welded along the inboard edge pressed against the outer skin to keep it from buckling inward if the tire carrier swings forward too hard. Several years later, I added a tether:

.

The other piece of red angle iron below & to the L is the reinforcement for the '83-96 t/g strike bolt mounted through the '78-82 hole in this '82 body tub.

Owner caption July 2003 · Photo 491 of 5000