Help for identify an Omega Seamaster Lady

Dear all, I need your help to identify this nice vintage Omega for lady. It is almost new (it was in an old jewellery inventory, new old stock) and it has the film on the back and the tag, but i cannot exclude that they have been re-inserted later. From the back it seems to be from the seamaster series but there isn’t the text on the front. I would avoid to open it since i haven’t the adequate tools now! It should be from 80’s but i’m not sure. Thanks in advance for your suggestion!

As mentioned. 60’s model. Doesn’t look NOS. Appears to have marks all around the watch or maybe fingerprint marks.

H and M hands in average condition. Dial should say Seamaster to match the case.

plain design of the times and not the most desirable of women’s models. If inherited. Inherited value mainly as it’s a woman’s model

I confirm that there are a lot of fingerprints in the photos. it seems to be unused. I’ve made some research with the serial number 23363031 and the reference ST 565.806 and i’ve found other information that corresponds to the watch. But is strange that with this reference is not possible to find this model on the web! I’ll continue my research trying to find a catalog from 1966! What could the movement be in this watch in your opinion?