LEER Cap Rear Window Removal

I'm getting ready to paint match my LEER cap, but i'm having some difficulty removing the rear window / gate. It has the same frame / screw setup on the inside as the side windows, but something seems to still be holding it on. I'd really hate to need to mask around this and miss a spot painting. Any ideas?

I have a feeling it as to do with these 2 fasteners, but they don't come through on the inside? I'm a little lost. This is the only window still on the cap right now.

 

I had to drill those out on mine. I just used some large coarse thread screws to replace them when I put them back.

Not the greatest photo, but you can see them here:
https://www.tacomaworld.com/threads/1st-gen-topper-rebuild-and-internal-frame.694546/

 

Ah that makes sense. I wonder why they have the 2 different methods for attaching that back glass?

 

I think the back window frame tends to spread apart so they ended up designing it with rivets. That doesn't really explain why they didn't just use screws (maybe a security thing?)