Anyone know why I have steel Sill plates?

After sorting out the inside of my 1951 chev sedan I found 2 steel sill plates. I think that maybe they came from a pick up truck. When I tried them on the car they fit exactly, so now the question, are they from a pick up or what?

 

What vehicle?

 

my '50 Chevy Sedan Delivery has steel sill plates.

 

Lobucrod thanks for the info that could explain it. I think the previous owner had one of them too.