Difference between references 4520.31 and 4820.31.01

Hello again OF!

I have come across two very reasonably priced cal.651 omegas (hand winding, thin, dress watches with small seconds in stainless steel - my weakness!). I have a question regarding the difference between the two reference numbers, as information on these models is scarce. See pictures below. The only differences I can see is the color/finishing of the dial, though that could just be due to the lighting of the photos. Any ideas? There is a small price difference of about $100, with the 4820.31.01 being the more expensive (possibly because it has the original Omega buckle on the strap??)

Many thanks.

REF 4520.31:






REF 4820.31.01:

Wonderful, thank you! That makes sense, after seeing several similar watches with the same reference on bracelets.

Go for it, here an old picture of mine.

Well, thought I would update everyone. I am now the proud owner of my first Omega! I bought two new straps from Delugs and couldn't be happier. Hopefully the first of many to come...

Hello!

Because this is in a similar vein and you seem to be knowledgeable about this sort of thing, I was hoping I might be able to get an answer to a similar question. While looking at the same/similar watch model, I have noticed that some of these watches have a 125.0150 engraved on the inside of the case and some have 125.0050. Would you happen to know (and be willing to explain) what the distinction between watches bearing a 125.0150 and watches bearing a 125.0050 is (if there is one)?

Many thanks!

Thank you so much for the incredibly prompt response!

Please forgive my ignorance on this subject, but would it be possible for you to elaborate a little bit more? Looking at photos online (admittedly not the perfect method for determining differences in bezels and case backs), I am not able to make a clear distinction between the bezels and case backs of watches marked 125.0150 and those marked 125.0050. I have noticed those marked 125.0150 appear to be slightly more likely to have a golden bezel, but not all appear to bear this trait (most appear to be silver). Otherwise I’m not currently seeing a difference with my (admittedly untrained) eye.

For instance, would it be able to identify this number for the two watches OP originally linked simply using the provided photos?

(For reference, I’ve been watching the ebay shop closer0924, which appears to be a reasonably reputable vendor from what I have seen on other watch forums, for a similar watch but I’m hoping to have all the information before taking the plunge. OP’s question was almost exactly the same question I had been trying to determine for quite some time, and I wouldn’t be surprise if the two original watches pictured were the same ones I had been looking at earlier this year.)

Again, thank you truly and sincerely for your input; this watch model is one of my ‘grails’ and I really can’t say how much I appreciate your insight and expertise.