Wanna sell it for $10? If I were you I'd sell it to me for $11 but seriously, go to an actual Omega Dealer and have them send it to wherever Omega has there technicians ( Rolex has them in Texas and New York ) to authenticate the watch and do a full service on the watch. This may cost you upwards of $500 or more, but if it's authenticated and freshly serviced it can be something you can pass down to your children. If you just want to know how much it's worth or what it is, it's an Omega Constellation and it's worth $10 : )
IMO that is bad advice - this watch does not need any authentication by Omega - the experts on OF can do this easily for you.
Have it opened by a versed watchmaker and post pictures of movement and inner case back here on OF and you will receive the information you need.
And as already mentioned by @X350 XJR do NOT send it to Omega - it will cost you a lot and there is the risk that they replace parts or polish the case which will considerably lower the value of the watch.
Have it serviced by an independent WM and have the wrong crown replaced then you will have a reliable heirloom which will bring you joy for decades to come.
Do NOT send it to Omega. Omega unfortunately often does not respect vintage watches.
Serial number dates to ca 1964.
If you intend to wear have it serviced by an independent watchmaker versed in vintage watches. DO NOT have the case or bracelet polished.
Great looking watch with a fairly uncommon dial and bracelet, which is worth more than the watch head itself.
A metaphor RE polishing that may help you to scope the opinions here:
If you’d inherited instead a 68 Mustang from your father, with its original paint job that looks great from 10’, but from 2’ you can see every little nick your dad put on it ... then having it “polished” would be like having the 68 stripped and repainted.
Now, some people might choose to strip and repaint, and it’s their car, so...
But for most around here, we’ll take a 10’ original paint job all day long (and for related reasons, it will be more valuable, collectible-wise).
I feel obligated to point out that a proper case restoration would do no harm.
Tom why say this? A case "restoration" will indeed harm the historical as-his-dad-wore-it condition of this particular watch. It is an heirloom. He didn't buy it at a pawn shop.
I somewhat resent the efforts to force me into the orthodoxy, by the way.
I only got a short explanation but machines and fixtures to hold cases to do brushed and polished finishes in a controlled manner instead of freehand, is my understanding.
And, he has a delicate touch. That 166.010 stainless case was previously refinished what appeared to be freehand and he's restored the curved sides that originally came on that version of the case so that it looks factory-produced. He was also able to reduce the effect of years of battering without losing any sharp edges. It was not and could not be a perfect job but it is substantially better than it was, and I can't wait to see the complete watch with refinished beads of rice bracelet when he has the movement finished.
You seem to take offence on practically every different opinion lately. No one is "forcing" you into anything. You do however have some fairly rigid viewpoints concerning how watches are maintained...