Vintage Omega Chronograph Ref. 2439 Cal. 321 ID Help

Tomas M. · Mar 30, 2026

Hi all,

I inherited this watch from my wife's grandfather. I have not much information yet, other than the quick feedback from a juweler who told me it is a calibre 321 (but not even sure this is correct). Maybe it could be 33.3 or 27 CHRO?
I have not taken it yet to a local Omega dealership, but it is working flawlessly. Does it make sense to have it serviced?
Anyone who can give me more feedback on model type, calibre and year? I don't have any pictures from the inside as I don't dare to open it myself.
Brgds,
Tomas

mac_omega · Mar 30, 2026

Def. not a 33.3 because it has an hour counter.
Either it is a 321 or its predecessor 27 CHRO AM PC.....

DirtyDozen12 · Mar 30, 2026

Maybe it is a reference 2439? The examples of this reference that I am seeing use caliber 321.

Notably, the dial appears to be original. This is hugely important to collectors and the value of the watch. If you choose to get the watch serviced, make sure that the dial is not refinished or even cleaned in any way.

Tomas M. · Mar 30, 2026

DirtyDozen12
Maybe it is a reference 2439? The examples of this reference that I am seeing use caliber 321.

Notably, the dial appears to be original. This is hugely important to collectors and the value of the watch. If you choose to get the watch serviced, make sure that the dial is not refinished or even cleaned in any way.

Other than what I see from reference 2439, mine does not have a tachymeter and Roman numerals (XII, II, IIII, VII, X)...

gatorcpa · Mar 30, 2026

Tomas M.
Other than what I see from reference 2439, mine does not have a tachymeter and Roman numerals (XII, II, IIII, VII, X)...

That doesn't matter.

https://www.omegawatches.com/en-us/watch-omega-other-omega-ot-2439

Omega would produce many different dial styles for each case. Looks good to me.
gatorcpa

DirtyDozen12 · Mar 30, 2026

Tomas M.
Other than what I see from reference 2439, mine does not have a tachymeter and Roman numerals (XII, II, IIII, VII, X)...

I am not an expert in Omega, but for Longines it was typical for a given reference to be offered with multiple dial designs. Below is another example without a tachymeter scale.

Source: https://www.proantic.com/en/1189287...graph-18kt-rose-gold-ref2439-cal321-1953.html

Vintage Omega Chronograph Ref. 2439 Cal. 321 ID Help

Tomas M.

mac_omega

DirtyDozen12

Tomas M.

gatorcpa

DirtyDozen12

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