To my eye, the relative height of the crystal (above the plane of the bezel) is always the give-away. If you are fortunate to have 1 of the low-profile rep cases, the difference is minimal & it is doubtful that the average gen owner or collector could ID it as a rep without close inspection. And, even then, it may pass
Always best to phone Ofrei for info or to place an order with a part number (unless you ask for him, you are unlikely to speak with Bob). Here is a summary of the most salient rules regarding emails to Ofrei -
Gen is definitely on the left. By-Tor wrote the definitive review of the 116520 & the dials have been top-notch for quite some time (to the point where I have twice refused amazing deals on gen dials because they were not sufficiently better than my rep's to warrant the time it would take to swap them ). Unfortunately, they have a way to go on their cases.
Depends on which crown is fitted & the condition of the crystal & seals, but I believe Rolex sports watches, unless otherwise specified, are spec'd to 100m.
I am better with vintage, but this does not even look like a good rep, which explains why you got it 'for quite cheap'.
With so many serious collectors literally scouring ebay (& most other online sites that cater to vintage Rolex), it is highly unlikely that a good quality, gen Rolex piece would go for cheap. That just does not happen anymore.
Can you be specific as to what parts for an ETA 2836-2 he cannot find? Has he (or you) tried cousins or julesborel for starters? ETA parts are stocked by a number of parts houses. Or just buy another 2836-2 & transplant the gmt parts.
In order to be accepted within the Rolex service network, a watchmaker must (regularly) pass a rigorous test of knowledge/experience & have the appropriate tools/environment required to repair Rolex watches. I have never heard of different levels of acceptance -- you either meet Rolex's standards (& get an account) or you do not. You might try some other ADs.
Rolex USA recently tightened the reigns on independents within their service & parts network, so it is pretty unlikely that many would be willing to risk their account in order to sell a part to a retail customer. However, a good indy (with a Rolex parts account) should be able to replace the part without forcing you to pay for an overhaul (unless it is needed).
That course is about pocket watches, which are similar to, but not the same as wrist watches. Many of the skills, tools & procedures can be transferred over to wrist watches, but the TZ course, which I took several years ago, teaches you how to repair wrist watches & they use the same ETA movements you find in most modern reps. So it is much more useful to RWG members.
Interesting, but an odd choice of end links. I have only ever seen that combination on 1 1675 & I suspect the bracelet came from another watch.
Here is Yuki's
And here is a gen for comparison
In general, I agree with automatico's comments. But I would add that if the crystal is cracked, moisture is a likely result. If the moisture just appeared, you should be able to dry it out. But if it has been there for more than a few hours, internal damage may have already occurred.