Am I purchasing some legit omegas?

Yeah...
For most of the times I only serviced modern omega's starting with cal. 1120 upwards till 8500 and some other brands with generic ETA movements (per omega instruction on april 2017 that omega movement below 1100 have to be sent to HQ to service). I'm still a bit new in the field as I just began 2 years ago since I've graduated from school. Thus I'm starting to learn about vintage watches as well as how to service it on my own on my own watches since I saw some customers brought along some of theirs and it piqued my interest. And yeah for opening or closing a watch as long as it's not a monocoque case should have be no problem, checking the performance, regulating, cleaning etc as long as I don't ask any sparepart from the admin and it doesn't hindered my daily job and quota per day.