I have a RTS, and there is no part number on the key. If I get some time I'll take a picture and post it. However, I do not think the keys can be shared between RTS's, so most likely you are going to have to find someone to replace the locks if that's even possible. The mechanism for the locks is fairly 'complex' at least in terms of being able to just swap in a new lock.
Also, you do not really need the locks unless you are using the Porsche rack accessories. The locks serve two purposes, make the RTS look nice, and keeping people from sliding the porsche ski rack, bike rack, etc. out of the rails. If you are using aftermarket racks you do not really need the locks, because the rack is assembled with screws.
