Prob a Franken. As you say the 1109 and 1111 were COSC certified. The 1108 and 1110 it seems were not. That said Omega have form from earlier times for putting some through certification and others not with the same calibre number. Do you have the PIC or case number for your model? If so, maybe check what movement it should have had. The case number might be stamped on the bracelet. The Pre-Bonds seem to use the 1111 or 1109 in my experience. Can you show an example where a 1110 was used?
Those are just the bracelet numbers so not a lot of use. Sometimes they stamp the case number, of the format XXX.XXXX on there but not here. Do you have any original papers? If we had the PIC or case number we could check what calibre was originally fitted.
I did a quick search simply on "Omega Constellation Manhattan Auto" and I got the hit below which looks like yours. This one has the certified 1111 movement:
https://www.ebay.co.uk/itm/285738956053?chn=ps&_ul=GB&_trkparms=ispr=1&amdata=enc:1CeMYnEPXRT2WWDDRc_SNCw2&norover=1&mkevt=1&mkrid=710-134428-41853-0&mkcid=2&mkscid=101&itemid=285738956053&targetid=1646683156259&device=c&mktype=pla&googleloc=1006524&poi=&campaignid=17206177401&mkgroupid=136851690655&rlsatarget=aud-1165553645205😜la-1646683156259&abcId=9300866&merchantid=6995734&gad_source=1&gbraid=0AAAAAD_Lr1e7Qz8xJvxPrxFNE8m_bens_&gclid=EAIaIQobChMIz5aG59X9hAMV24lQBh1ujw7LEAQYASABEgJ-uPD_BwE
This suggests your PIC is 1500.30, if that is so, it should have a 1111, there are zero google hits for that model with the 1110 instead.
I don’t think it’s a Franken at all. I have the same watch with original box and papers. Received from the original owner who I’m sure never tampered with it. Cal 1110 and Chronometer on the dial. I’m sure it has never been or is way overdue for a service but still keeps incredible time on par with my 3861 Speedmaster.
Serial numbers under 50 million cannot be looked up on the Omega Extranet - Omega wants you to buy an Extract of the Archives for those.
I did look up the bracelet, and from that every watch that this bracelet was used on - only one matches the OP's watch, and that is the ref. 15003000.
I want to contribute to this matter as well. I don’t know if it’s really necessary and although almost a year later.
So I obtained a 368.1075 through eBay and stumbled upon this thread while researching the reference. I researched the reference beforehand and saw the rotor and the details on the movement of the one offered on eBay was a bit different than the one in the articles and informations on them. Then I stumbled upon this thread and the movement pictured on looked the same and turns out it’s also 1110 calibre in the one I ended up purchasing for a fair price in the auction.
Anyways what’s interesting and also leads me to believe that their was a moment during the eighties (may be in the early stages of the automatic manhattan production) in which they used the 1110 usually non chronometer certified movements with the chronometer dial pictured above. I believe so because it’s the same dial on mine with patina/tropical aspects and also a movement serial that’s almost identical to the one by @Aroxx except the last digits are different. it’s either 47523231 or 47528231 -> I can’t make out if it’s an eight or a three either on mine… but it would be a crazy coincidence in my opinion if someone’s building identical Franken watches with the serial movement numbers being so close to the other!… anyways anything is possible but I believe they used them for some reason although they wherent chronometer certified with a chronometer dial in the early stages lf the automatic manhattan 368.1075. and good thing though - mine is keeping great time - it’s only running + 3sec a day.
