Welcome to the board.
I take it we are talking about rear fenders here? Yes the 53 and up are readily available as they used them up through the 70's. The basic bed box is the same with the exception of the fender bolt holes.
There is no such thing as reproduction steel fenders for the 48-52 trucks (the 48-50 fenders are slightly different as well as there was a raised panel on the bedsides on the earlier trucks)