Did you read what it says about the lock? William Ketland,Sr. began his firearms company about 1755. W.Ketland on the interior face of the lockplate, not the exterior face of the lockplate required by the British beginning in 1768. AL
So are you selling it?
It also mentions the same thing you did in another post regarding the Merrills as gunsmiths, and the one being hung by the britts.
As for the ebay lock, the internally signed ones are earlier as far as I know, but I don't know if it makes them pre-1768. Maybe JV Puleo can step in with this info, as he has done a lot of Ketland research.
I agree with the others here on value,,,, to optimistic unless you really needed it for a gun.
Then there's the comments about the lock comming off an old gun that one of the Merrills owned!!!!, Yikes, what happened to the old gun?
John