B Body buckets in an A body???

Hello all,
I have some decent B body bucket seats out of a 73 Charger and I am thinking of putting them in my 73 Swinger. Obviously, the foam and covering are different in A to B Body. I've heard chatter the frames are the same, or similar enough, to swap. Is this true? Reupholstering them goes without saying. Would A body seat foam and upholstery from someplace like Classic Industries work? Has anyone tried this?
Yes, the seat frames should be the same, the rails, the part that the frames attach to the floorboards however, ARE different