Help me! Vintage 2505 circa 1950 restoration!

My girlfriend's father had this vintage watch, it's in pretty rough condition currently, but the movement looks good (I think) - I currently have the watch in my possession, my intent is to restore it to perfection and then give it back to him for his birthday. Based off of some google searches, my research has identified the watch as a 1950's/49? Omega Ref 2505; there seem to be a lot of dial variations to this model with the same movement, but I cant find my specific dial. Can someone with some strong vintage experience please tell me everything you know about this beauty (soon to be) - and the best way I can go about restoration? I took it to the Omega store today and they said that without the original case, they can not touch it. The original owner said that his father had sold the original case and bracelet (18k gold) and replaced it with this stainless steel generic case. The watch came from Argentina (his family is from there), and apparently, the reps at Omega couldn't even order the extract for it; so I have no concrete information as to what this watch is, only research based assumptions which are open to speculation given my lack of expertise. Help me turn this beast into a queen. Any and all feedback is welcome.

Note: the watch keeps time surprisingly accurate given what it looks like (still want to get it serviced, but Omega wont touch it)

Ref: 2505
Calibre 265, 15 Jewels
Movement # 11757700
Case/Crystal: Non-genuine (generic) ..*advice for as close to genuine as possible replacement needed

Standing by for After pics!

Best of luck!

I don't. I stated that the model specs were open to speculation, admitting that I wasn't 100% sure....I did however stumble onto this link, the bottom right model seems to be very close to the one I have in my possession, and that was identified as a 2505 - hence my presumption.