remohbill - sounds like you have what's on the
options list as "Air-Matic Seat", also shown in the assembly manual as RPO 269 "Air Cushion Seat" - you'll find some of the construction details in the assembly manual, but that's about it, you won't find any parts available, I'd think they were mostly used in the big trucks [I saw one in a 56 5ton], likely beat to death long ago
and yeah, a picture would be really interesting, we can never get enough pictures!
Bill