Well, I saw an S-class yesterday and it seemed like the MBZ fleet at the Pen were in roughly the same category, so I trust you're correct.

If the RR is indeed about 10 years old, that would make good sense if they bought it in connection with the opening of the hotel, now nearly 10 years ago. In any event, personally I wouldn't get all bunged up about how old the car is. You're not buying it, you're renting it. From the airport to the hotel is 45 with traffic. I can see how the new specially-designed ones in HKG are better, but this isn't something I'd get persnickety about. YMMV, obviously.