Re: 3570.50 is not a caliber 1863 watch. The mystery
: deepens. This model has acrylic crystal and sapphire display back. It has a serial number of 77061xxx. Around the outside of the back is Omega and symbol then the word "Speedmaster", followed by watch worn on the moon etc. So I think that the confusion lies with the seller because there is no documentation but came from a jeweler in mint condition with hang tag. We all know even ADs get their products mixed up. He is a longtime, well known, internet dealer in pre-owned watches. Now could the standard solid SS back be replaced with an Omega transparent back. Are they interchangeable? I don't know. The only source would be an Omega service center. As I said the watch should be in my hands Friday and should be able to find out more. Interesting. What does the case serial number say as to date of manufacture? I appreciate your time and efforts. Thanks
Not sure what Omega website you are looking at, but I just looked
: to make sure they had the correct information. Ref#3570.50 is
: listed with caliber 1861, not 1863.
: The watch with a see through back should either be a 3572.50 or a
: 3573.50. If you see anything that indicates the watch is 3570.50
: but has a display back, something is wrong. Either the
: documentation is wrong or the watch has been modified from its
: original version.