You could have up to 4 remote keys, and then manual valet keys aswell. Keys 1-4 could all be synced/used at the same time. If one has been replaced at some point and you have 2x key 1's for example, then as mentioned above, you can only have one of them synced at a time - which will mean that if you sync one, the other won't work for the remote, until it is resynced - and then the first one will stop.
If you can sync them all up, then you will have 3 keys all of different numbers.
You can find out (if you have memory seats) which is key 1 and 2 by using 'lazy unlock' (only works if the vehicle has been superlocked though!) which will set the seat memory to either preset 1 or preset 2 if the unlock button is pressed and held on the remote when unlocking. I used that method to find out that I have key 2 for my P38 (Sticker has rubbed off over the years). I set the seat all the way forwards and programmed it as preset 1, all the way back as preset 2. Set it back to the middle, took a deep breath and superlocked it... waited the 15 sec for it to super lock, and then 'lazy' unlocked it and noted which preset the seat moved to.
I *think* you can only get new Key 1 fobs from the dealer these days... though I don't see why you shouldn't be able to get the others, as it's just a change in the programming of the fob to ID it as a different key I would imagine!
