PRR Brass Key - Authentic or not?

[timof5stars]

I picked up a brass key that appears to be a Pennsylvania RailRoad key.

(I'm a bit skeptical due to the very low price I paid. Looks like it could be authentic but, on a related note, I was at a flea market last weekend. One vendor was selling a "real old, very rare, excellent condition" switch lock (similar to Adlake models). It was stamped with "PRR" and "Signal Dept.". When I picked it up I was immediately suspicious - it was far lighter than I thought it should be. There was not a single nick, scratch or dent on the entire lock. There were no signs of wear. I pushed back the dust cover and the inside was spotless. He wanted $60 for it. I sat it down and walked away.)

Anyway, here are the pictures of the PRR key. Authentic or not? I hope I'm getting better at this. I'd prefer not to add to my pile of reproductions...

Thank you for your time. Please let me know if I need to provide additional photos, measurements, etc.