1958 seamaster300 2913-3 ( omega logo stamped into the case lug ) appreciate any info regarding this stamp and why ??

G’day Legends I’m after some advice on a vintage 2913–3 genuine case , stamped on the underside of the lug , to me it looks like a genuine stamp ( slightly worn out but not polished off ? ) and not an engraving or aftermarket stamp I have spoken to a friend in the know and he isn’t 100% certain either , I will share photos of the watch itself and also close ups of the lug “omega logo” , as far as I am aware this watch is 100% factory original from 1958 including the naiad crown , the only outsourced part was the bezel from Israel last year( original/genuine Bakelite insert ) to complete the watch . Thanks legends , I am hoping this is a case that could be limited in numbers but regardless it is a nice detail to find , I did read that Thanks for any help I am reasonable familiar with various vintage seamaster300 models but not by any means an expert , that is why I’m here aha , cheers

Chatgpt results : This strongly points to a rare, undocumented factory or assembly-line mark. In the late 1950s, during the very early production of the Seamaster 300 (first batches were still being refined), Omega and/or their case suppliers occasionally applied small internal control stamps for quality assurance, part matching, or inspector acceptance. These were never meant to be visible once the watch was assembled, so they are rarely photographed or discussed.

Grok ai results -
The anomaly is a small, clearly struck Ω symbol stamped on the underside (inner face) of one lug, near the tip. It is not deep engraving, not laser, not added later - it shows the same degree of oxidation and surface wear as the surrounding steel. It is very discreet (only visible when the watch is flipped and angled correctly).


I have spent considerable time searching:


• the entire Straight Lugged 300s mega-thread and related 2913/2913-3 sales & authentication threads (2015–present)


• dozens of auction catalog photos (Phillips, Christie’s, Bonhams, Sotheby’s)


• vintage Omega reference articles and collector databases (Vintage-Portfolio, Veblenist, WahaWatches vintage ID guide, Chronoholic, Fratello Seamaster pieces)


• Huguenin Frères case marking conventions (HF stamp location and style)


• cross-referenced early Speedmaster and Railmaster cases from the same period


To date I have not located a single photographed or described instance of an Ω logo stamped on the lug underside of any 2913-series watch (or other contemporary straight-lug Omega professional models).


My current working hypothesis is that this is a genuine early-production control, acceptance or assembly-line inspection mark applied either by Huguenin Frères during case finishing or by Omega during pre-assembly checks - a micro-variation that only appeared in a very small number of cases before the process was standardised. Because the mark is internal and not intended to be visible once the watch is worn, it would rarely (if ever) be documented or photographed by owners or cataloguers.

Yep that’s Dan , I use ai purely for info I may have missed but I completely understand that ai chat bots are only an info source so to speak not part of any authentication steps as far as I’m concerned, I am definitely enjoying the watch I have a 165.024 also and have a thing for these gilt seamaster300 dials