Ok, does this make sense? Back of pocket watch stamped "18k" but tests Sterling?

pcgs69

Picked this up today from an area looking to date around the 1870s. Gave a nice silver tone and it was surprising to see it pop out - only a couple inches deep. Definitely looked silver and sounded silver. But, the inside has an 18k stamp in it and a serial number 58285. It's definitely gold plated and tests Sterling silver. My questions:

How common was it to mark gold plated items with just "18k" and also
any idea of age or the watch brand?

First set of pics are of it uncleaned.

.

ricko

Gold plated sterling was common, and advertisements often stated a gold purity for the plating - however, I have never seen a plated piece stamped with the Karat. Cheers, RickO

123cents

Part of a pocket watch case. Very cool!

johnny9434

not a bad find and it cleaned up nice to

bsshog40

That's a pretty cool find. I dug up an old watch in my backyard about a year ago. All the pieces were right together.