I won't be home for another couple weeks so I can't take a look for you, but, I took some pics years ago for someone.
I don't know if they will help, but, PM an email address and maybe I can figure out how to send them to you. Computers and I do not get along well together.
I tried to figure how to post them here, but, it hasn't worked.
I'm assuming a 31 std top is the same. At least I think its a std top.
From what I can see in the pics, the wood is fastened with screws. Thats all I say right now.