Ah ... the ole Assumption Monster raises its ugly head yet again.
The reminder for all of us is this .... when dealing with used parts, never assume they are what you think they are (or want them to be). Ask questions. Confirm.
Just because it *looks* right doesn't mean it *is* right. When things that are supposed to fit don't, there's usually a really simple answer as to why not. If it isn't forthcoming, back up a few more steps until it is.

Just bringing this up as a gentle nudge to the greybeards to remember before we get carried away and head off to the fabricator shop to make things work that aren't working. Been through this myself.
Sometimes, you just have the wrong parts.