new upholstrey for manual seats

I bought some new leather seat skins for my 94 dodge stealth off of ebay.  They came with a large opening not the zippered back panel mine have.  I have been trying to figure this out, but it appears that the manual seats had a zippered back panel on the skins and I am guessing that the electric seat had a large hard panel that made up the back of the seat.  Is this right? I assume this was to gain access to a motor or something in the power seats.  Easy enough to get panels off of ebay, but I am told you can't use them on a seat that didn't come that way.  I am trying to get this straightened out since this stuff is not cheap.  Any help is appreciated.