A question for the more experienced here, particularly with an eye towards vintage.

Someone shared some photos of an Omega Constellation piepan on FB.

Based on the photos I think that it's a gold capped ref 2852, What catch my eye in support of the 2852 ID are, curved lugs rather dogleg, the lug length, the octagonal crown and the 2-tone caseback.

Now I am basing that ID on photos taken via a potato, of what may well be a very poor condition watch. I am hoping that the condition of the case back, points to a scuffed crystal rather than a ruined dial.

Anyone with a better eye? Please, jump in and steer me straight on what this might be, I'd also appreciate a steer on what a fair offer might be for this one.