lock key

Please tell me more about this hollow barrel key. The only marks appear to be a “12” and a small “4” at 3 o’clock, and perhaps a larger “4” at 6 o’clock, all on the same side. There are three scratches or marks and since they are on both sides they may have been added. Based on the shape, I...

I would believe this is a Union Pacific lock key. My question is what does the S stand for, from what era and what would the lock look like. This came from a lawn from an 1820 Stone house in the Finger Lakes of NY- same house frome where I posted that nice Marine Button last year. I worked that...