1974 Trans Am - Bucket Seat Bolts?

[MART60]

This is what holds the two back bolts on the bucket seats.

I've never seen a nut like this in my life, and I have tried a hammer and punch.

I may just Cut & Grind off, then put regular seat bolts in.

I want to get my bright red PUIs on.

Thanks, one and all,
Mart