The link you included is not for a simple replacement pot--it's for an MEC 2-band active EQ and complete wiring harness (for passive pickups).
If all you need to do is replace one of the pots, just look at the pot and see what the resistance value that's printed on the back of the pot is. It should be easy enough to find a replacement.
Mike
PS: The link for the passive tone pot and capacitor for the passive Corvette is
http://shop.warwick.de/product_info....te-passiv.html . That's 26.90 EUR--still rather expensive for a pot and capacitor, but a lot cheaper than 239 EUR!