I have a set of these top blocks that I currently have listed on EBAY. They have been used so the black plastic caps shown signs of this but I am sure for the money I have them up for, someone could repair and repaint the outers and end up will a really good set. Here is the link if anyone wants a look.
http://www.ebay.co.uk/itm/141466356854?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649

I'm not trying to ruin a sale, but since your listing says "what you see is what you get", I'd like to point out that your for sale Gen I set is incomplete. In addition to what is shown in your listing there is a long cross bolt (it goes all the way from one side of the bike to the other) and two vertical bars missing. Not quite as easy to source as just missing bolts would be. Perhaps you have the missing parts but didn't recognize them as part of the set?
The whole set should look roughly like this Gen II set in Fred's photo below: