Hi Shannon,
We just finished refurbishing an 88. It had 3/16" rivets, mostly 3/8 long, but some a bit longer, I beleive. I'll look tonight and let you know.
www.bigflatsrivets.com has the correct tools to hold the round side and set the inside with an air hammer tool. I bought my rivets from
www.mcmaster.com in Atlanta. Just get on and go to fasteners and sealing, rivets, round head, etc.
They were cheap by the bag of 100.
Good luck!
Greg
