Rad-a-cage bolts

I have a 1999 Mobius with a Rad-a-cage tower that was installed aftermarket by the dealer. I have to fold this tower a couple of times a week. I do this by removing the large allen head bolts that connect to the mounting brackets in the front and fold it backwards.

PROBLEM: The bolts are starting to gouge the threads in the tower arm and/or the mounting bracket. Apparently these are aluminum and the bolts are stainless?? Because the bolt threads really load up with the surrounding material but I can eventually force the bolts out by unscrewing them. Then I have to take a small chisel to the threads to clean them up. This leaves the threads on the bolt a little dinged up and more prone to galling the next time they are used. This does not happen every time so not sure what is root cause.

REQUEST: I need to know the specs for the bolts, size, material, strength, so I can get a couple new bolts. Could use some ideas on the best place to buy them. Are there other options? A new tower is not an option at this time.

Any help on this would be greatly appreciated.
Thanks
Dave