Hiya Col,
I have similar issue- recently finished throwing mine back together, and also bought a frame pack from Brian but can only use a couple of the items.
It seems the correct listed 67-1251 is I think a 3/8" stud, but mine has a 7/16' stud through a sleeve from memory about 9/16" od.
Can't recall if that's how it came or something that I've improvised, as it's all compiled from bits, but figured a way to live with it but I've been curious whether others have anything same..?
Guess that's not much help for now, but at least you're not alone-
Cheers ,duTch