I am by no mean an expert, but I’ll get started anyway!!
The hobnail dials with arrowhead markers are pretty uncommon for this reference and incredibly hard to find, so that’s a great point. One has to say they look incredible. Your dial has quite some damage from water perhaps at some point (the crown is not original or signed) and on the edges. The dial is clearly the best point about the watch in my opinion, so the question is really how this damage renders in real life, rather than in magnified pictures…
A few screws missing on the movement, plus the regulator position suggest it will need a service. Maybe finding the correct crown to replace it during the service would be a good idea to prevent further damage to the dial later on. This needs to be factored into your final price, somewhat. Make sure you identify a competent watchmaker.
The case has been polished, but these references don’t have sharp edges (someone correct me if wrong) so I’d say it’s less an issue than on other references. The observatory and stars are quite soft though.
Ultimately these go for much higher prices normally, although condition puts a large premium or discount. If the dial looks nice in person and you’re ok with the patina / damage, then it’s a very cool watch as your first. Definitely not quite the usual first vintage buy!
There is one for sale in the private section at the moment.
https://omegaforums.net/threads/omega-constellation-2652-hobnail-arrowhead.165825/
I have seen another sell for 5500€ recently from a dealer with an almost perfect two tone hobnail dial (although I can’t remember if the reference was exactly the same).
There is a thread on these as well (check the listing) if you want more info.