The corrugations are different.
You can make it work if you are replacing the whole thing but it is not optimal.
I bought six 20x48" panels from Mill Supply when I got after my bed eight years ago.
They seem to have held up despite the drop-in polyethylene bedliner.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.