Wheel Well Squares
On my 74 Tradewind, I had one of those on the right rear but it was on the top. When I removed it I noticed a sliver of a gap in the floor. It looks like there is a corresponding piece on the bottom. I think it was to close this thin gap. It might of been close to 5:00 on Friday when the jig saw that cut the floor around this area was turned off in 1973. I think its an aluminum bandaid in my case.
"It takes a village to raise a silver twinkie."