I saw these too...
Gave Alcon UK a call as I could not get any info about these calipers on their website. Alcon said that a bunch of these calipers were 'disposed of due to a quality issue' (their exact words). They didnt go into detail on what the issue was but DID say that it was NOT a safety critical issue!!
Now I'm not suggesting that the Ebay seller has whipped these out of the bin and is flogging them but Alcon did say that these calipers were rather specialised and not something you would normally see on the 2nd hand market.
Person also said that finding spares for them would be problematic too...
Shame, as the prices are not to be sniffed at..
TT