Rado63
·Maybe some others here can tell you the answer with more certainty, but I am not aware if the blue dial 3523.80.00 was sold on a strap. I have seen them on a strap, but I don't know if that's they way they were originally sold. If it was sold on a strap Omega often has a different reference number for the watch. In the photo you posted I do not know if this is the correct strap for the watch, it appears to be a larger width strap that the owner may have had and put it on the watch, which means there could be a bracelet somewhere. The strap has an Omega buckle, but the watch wasn't made for a strap that wide. It appears forced in between the lugs, but I could be wrong since I am looking at a photo. So where did that Omega strap come from? Selling the watch like this makes it worth whatever someone will be willing to pay. If a nice example of this watch in good condition and correct box and books was worth $2500 - $3000 then how much is a watch head that needs service, with no correct box or books, and perhaps a missing bracelet worth?