Ted,
Sorry and no offense, but you seem to have stepped in it on this one.
Your egg shaped holes and poorly fitted pad on the tumbler dont exist; they are artifacts of old, very dirty, grease (kudos to Buzz, who called recognized the grease). And the lock isnt missing a sear. Not all guns have or need secondary sears; this lock is from a live pigeon gun in which secondary sears can be a liability.
In terms of the price point thing, and quality you can produce for the price you are getting, the gun to which that lock belongs was proofed in 1946, used to shoot competitive live pigeon for almost forty years, and still functions quite reliably. Its a hoot to shoot trap and wobble doubles with it. It originally cost less than $100, equivalent to a little less than $1000 in 2015 USD. How many other values as good as that have you seen recently?
