I remember the storage locker story. I don't know if these locks came from that. I have seen pictures of boxes full of them. The company that made them went out of business decades ago. I think it was excelsior. I researched all that over 10 years ago and have notes on it somewhere. John Barton knows. You could get them reproduced in China, but the initial tooling and setup is cost prohibitive. That's why Barton went with flute case latches on his cases.
Most of the latches and locks you see on cases come from instrument cases. At least, that is the original use. Even the older latches on Harley tour packs are originally from a German instrument case company, Harley paid for a license to use the design.
Sam has been back at it for a while, occasionally selling cases and parts. He sells all the parts, including liners which he does not currently have listed.