One way to make those stamped numbers more legible is to rub them with a piece of welder's sopastone or Ivory soap, then wipe down the flat area. The numbers pop up like a neon sign. That's an old gunsmith's trick for finding serial numbers or proof marks on antique firearms.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!