Buddy Bucket TearDown / Assembly?

[60short]

This may not be the correct spot, but I figured id start with the most knowledgeable group, as the only upholstery section I could find was the FAQ...

I have what I believe to be an original (67/68) set of buddy buckets ( I know they weren't offered factory in 60-65) in my 1960 truck.



I have a broken and stripped stud / bolt that holds the seat to the frame :



and I was wondering if anybody has any insight into the best way to tackle these.

I see that I can adjust the sliders to be able to unbolt from the individual seat frames :



but I'm not sure how to tackle this stud, and the removal, and if I should do all of them at the same time?

Are these square headed / swaged into the hole?

There are also some of what I assume were gliders or something -





does anybody reproduce these?


and finally, does anybody have any insight into if this "spacer" is stock and if its supposed to be held in / on by anything?