Views on the vintage omegas?

Not knowing a watch maker or pricing I'm scared of vintage watches.

A few bits of advice:

1. Try to see if the seller can provide some kind of documentation that it was serviced (dissembled, cleaned, reassembled, correctly lubricated, adjusted to run accurately). A lot of sellers advertise a watch was "serviced," but that means many things to many people.
2. Search up the six digit reference number on the inner case back. Compare it to others online to see if the watch is all original.
3. Search up "C-case" Constellations, which is what your watch is. They are still an affordable way to get into a vintage Constellation. The later 1000 series calibers are usually cheaper than the 500 or 700 calibers. 

Thanks! well I saw this listing from this website (https://www.vintagemasters.eu/)  . I’ve contacted them about the serial number and also condition of the movement. So yeah, probably i’ll get more info by tomorrow, fingers crossed! Anyways, is there a big difference between the 1000 series and the 500/700 ones? 

I've looked at the listing & would think it isn't serviced as the vendor doesn't mention it & they say there is a small amount of dirt under the crystal, which should have been cleaned had the watch been serviced. 

Yes, a big difference. The 500 and 700 series calibers are generally regarded as the finest automatic movements that Omega produced in-house until the co-axial. The level of finishing is quite high (plus that swan neck regulator 😍) and the performance was legendary. Omega was about to certify 100,000 cal. 561 movements in a row as chronometers. The 1000 series movements features some cost-cutting, but I honestly think they get a bad rap. I have an Omega with a cal. 1020 that performs flawlessly. The bonus with the later 1000 series movements over the 500 is a real quick set date, hacking and a higher (4Hz) beat rate. 

Ah yes you’re right! the vendor also messaged me saying that they’ve checked and saw nothing wrong that requires it to be serviced. To be honest, I’m not sure if I’m gonna take my chances with that haha

It sounds to me like they would only service the watch if there is something functionally wrong with it (running & then stopping for example) I collect vintage watches & they all didn't keep accurate time when got them & needed to be serviced. I'd ask them how accurately the watch is running & if they can't answer that question I'd walk away. If you're buying from a dealer you are paying a premium so they really ought to service the movement in my opinion 

Vintage Omega is great bang-per-buck. Beautiful watches, excellent heritage, when Omega was really in it's first heyday. 

My vintage Seamaster has a caliber 751 movement, which was used in many of the cushion-case constellation models like the one you have pictured here. I got it serviced recently for $170.