67 barracuda front bench..center arm rest..with no seat back locks?

Hey guys I bought a front seat out of a 67 barracuda. It looks recently redone. But I was wondering if it was normal for those to not have a lock for the back rest. I mean, the back rest sits back firm but there's no lock. So to get in the back seat u just push the back rest forward. (Super safe right haha) Like I said it's recently redone it looks like so I was wondering if the lock was a feature they left off? I'd like to get it to lock.