75 Plymouth Duster

New to A body forum, belong to B body (62-65) so this question may be have been answered before. I need new floor panels for my 75 Duster but AMD only lists floor panels for models up to 74. I have looked at a few 74 models and can't see much difference in the chassis & sheet metal. Anyone know if the 74 units will fit the 75 or if there is a great deal of difference. If there is a difference is it surmountable (do-able).
I used front floor pans from Year One that were listed as up to 74. No problem. The difference is under the drivers seat. It is recessed and a second layer of metal bolts on as a heat shield for the cat.