Need help identifying these markings on my 135.020

BelWatchSpotter · Mar 17, 2026

Just got this 135.020. The seller told me it was gold plated, but the inside doesn't show the typical gold plated markings. I found a stamp on one of the lugs that looks like a 585 14kt gold stamp, but I can't seem to find any info on gold stamps on lugs on omega watches. Inside I found a stamp that I cant really identify. It looks like a "A-K", but now I'm thinking it might mean "14k" or something like that. Haven't had much luck finding any info on this so any help would be greatly appreciated.

My apologies for the bad camera quality, the camera on my phone is pretty bad and I dont have any other way to make pictures at the moment. If need be, I can maybe try to get a real camera this weekend to get some higher quality images.

Canuck · Mar 17, 2026

The A-K mark inside a case back that is stamped “acier inoxydable” (stainless steel) definitely is not a 14-K stamp! The steel back is stamped “made in Switzerland”, in which any 14 karat stamp would likely be marked as .585. I don’t have an answer for the .585 stamping on the lug. It is unusual to find a karat gold case with a stainless steel back.

BelWatchSpotter · Mar 17, 2026

Canuck
The A-K mark inside a case back that is stamped “acier inoxydable” (stainless steel) definitely is not a 14-K stamp! The steel back is stamped “made in Switzerland”, in which any 14 karat stamp would likely be marked as .585. I don’t have an answer for the .585 stamping on the lug. It is unusual to find a karat gold case with a stainless steel back

Thats what i thought too. But i found this thread with the same stamp in which it was identified as a 14K stamp.

https://omegaforums.net/posts/1218737/

Redsh1r7 · Apr 26, 2019

Peemacgee
Welcome @Redsh1r7

Do the papers state it is a 168.018?
With the dial configuration, case back style and recessed crown, it looks very much like a 168.010.

Unfortunately I only have a generic Omega Constellation booklet, nothing specific to this watch. It's still a neat thing to have.

I had assumed that it was a 168.018 based on the stamp inside the case back. The last digit looked like an 8 to me... but it might also be a 0... Based on the what I was told there were multiple watches given out at the time with the same engraving. I could certainly imagine a scenario where...

BelWatchSpotter · Mar 17, 2026

Canuck
The A-K mark inside a case back that is stamped “acier inoxydable” (stainless steel) definitely is not a 14-K stamp! The steel back is stamped “made in Switzerland”, in which any 14 karat stamp would likely be marked as .585. I don’t have an answer for the .585 stamping on the lug. It is unusual to find a karat gold case with a stainless steel back.

I must also add that the colour of the gold reminded me more of my other 14kt gold capped seamaster than it did of my gold plated one. See the photo i added for reference; left is my 14k gold capped, middle is the one i suspect to be gold filled, right is 40 micron gold plated.

Need help identifying these markings on my 135.020

BelWatchSpotter

Canuck

BelWatchSpotter

BelWatchSpotter

Similar threads

Need help identifying these Omega hands

Purpose of "hash" markings on some ETA movements?

What are these markings on Omega Mesh clasps?

need some help identifying markings

Need help identifying grandpa’s vintage Omega

Need help identifying this Omega Seamaster Model Number