Seat swaps?

[old Chevy guy]

My father has an 86 pickup 3/4 heavy duty.Its in pretty good shape and all but due to the ride height and that the seat is kind of worn out he is having a hard time getting in and out. I posted an ad on craigs list looking for a good used seat and got a few responces.So after all the background here is the question.Will a seat from a newer truck an 88 2500 fit in the 86 without a lot of mods?and what about buckets from a 87 suberban with they fit other than a few extra holes?What about a 67-72 seat? thanks for any info.