How do I move the seat back?

My 1950 Jeepster has the same split front seat as the wagon - fixed position. How do I move it back a few inches? Don't say diet & exercise! I can see the bolt heads holding the seat frame to the floor, but can't get under it to see if there are nuts or if there's fixed threaded holes. Thought I could do something myself, but I may have to take it to place with a lift. If you know anything about this please let me know - SOMEBODY must've restored an interior out there! Thanks much!!