Can a decent locksmith make a key for these locks if none exists?
Probably, but it likely won't be cheap. They'd have to pick the lock to get it apart to see the key code stamped on the cylinder and then cut a key. If the lock came out of a known truck with a door lock, it SHOULD have the same key as the door. The key code on the door can be found by removing the lock. That involves pulling out a keeper that's under the weatherstrip.
Another option is to send it to someone who has a collection of Briggs & Stratton pattern keys. I have about 150 different keys and was able to open the glove box lock from my truck.
