Hi gentlemen! Am thinking of pulling the trigger on this with serial number 18811409 but the inscriptions on the case back just left me wandering ... seller not sure about it as well.. any inputs?

 

Yes. Definitely not a vintage SM300 (the movement is vintage, but may not even be from a SM)

 

Watchco.

 

It is a Watchco. The 166.0324 was the number given to the replacement production cases.

 

C.552 not from SM should be...

 

Theoretically correct, 166.xxxx would be for a date caliber 563/565.

 

The replacement case back on my 552 SM300 has 165 0024 in the same etched style as the OP

 

Watchco or modern fake? I think modern Omega service replacement would be the most accurate description.

 

Shouldn't the hour markers go all the way to the tension ring?

 

Not on the genuine Omega replacement dials

The whole watch looks like it has the correct Omega parts, case, dial, hands, and then just put together with an old 552 movement, lots of people were doing this a few years back when the cases could be bought from Omega at a reasonabe price.

 

Possibly watchco, positively a service parts SM300 with a donor 552.

 

Still a cool watch as long as priced accordingly.

 

I thought I'd better check on this as they do on my Watchco 565. It seems that they don't on the 552 but they do on the 565. More about the 565 dials here: https://omegaforums.net/threads/questions-for-watchco-sm300-owners.58491/#post-724941