Thanks for the question, Kurt; and, thanks for the information, Tim.

The floor under my seat was mostly rotted/rusted away in 1971, when I got my Suburban. I had all the mounting hardware, just no floor. My jump seat is now "creatively" attached to the floor-metal, with reinforcement bars underneath.

'60-'66 Chevy/GMC Panel & Suburban Jump Seat Mounting Kit
This kit includes the factory-correct Suburban passenger jump seat mounting pivots & hardware for the '60-'66 Chevy/GMC Suburbans. This kit includes 4 mounting pivots and factory-correct mounting hardware.