Justin: the lock will serve you well. I think it might be just a tiny bit on the small side, but it would definitely work. Remember the Kuntz rifle you and I shared on the squirrel trail at Heffley a few years ago? That has a Chambers' late Ketland lock, and as I recall, neither you nor I missed a target after you started to share my rifle.
I have a 20 gauge Ketland fowler and Jim's lock is practically a dead ringer for the original lock...'cept mine has Ketland engraved on it!