It’s a rim lock yeah? I dunno, I always called them bear claw locks for the actually locking mechanism, yale keyway usually I’m my opinion, but they’re fun.
Put that retainer piece through the post and then it’ll be on top of that wire spring. The guide should fit. Throw the cover on and test the actuator with a flat head. If the thing locks you’re ready to rock.
I’m off to fold my socks.