Good thinking BK - I'm about to hit 5,000km myself. Some people keep the spare untouched, and just rotate the 4 on the car, then when it comes to buying new tyres you only need to buy three (but you are then locked to staying with the Dueller's, and end up with a worn-out spare <_< )
Just to confuse the issue I found this description and diagram...
Silly question and I haven't had the need to check, but the spare is a full-sized alloy, and not a full-sized steel rim?
Cheers