Michael walked into the centre of town, and bought a Rolex. Not just any Rolex: his Rolex, from the same jeweller, at the same price, and with the same tiny scratch on the back of the casing. He watched the assistant fasten it, carefully noting the mechanics of the process, and figuring out how he would manage it for himself. The watch felt reassuringly solid on his wrist, reminding him of how his life had been before: the good and the bad, and grounding him after his earlier panic.
Hooking his thumb through the hole in his hoodie's sleeve to conceal his purchase, he left the jeweller's shop and headed for a street where he might find his other major purchase of the day.
Now, I'm pondering whether I've put enough information in that passage and/or the rest of the story to explain why Michael loves his (second hand) Rolex so much that he owns it in both the possible timelines we've seen so far, even though in the first timeline he has practically no other trappings of a rockstar lifestyle and in the second he's going to have a lot of trouble getting it on and off without help.