Thank you for sharing. It looks to me like a Henry Ritchie lock/key. Patented in 1849, patent number 6252.

https://www.google.com/patents/US6252

Hope that helps!

It's a shame the bow is broken, but that is quite a nice lock you are repairing. I'd love to see if when it's fixed up.

FYI, if the person you are repairing it for happens to want to sell it, I'd definitely be interested.