You've found one of the rarest of all items from Campagnolo. Much like the super-famous 1955 double-struck lincoln penny (which last sold for $46,000 at auction in 2002):
http://en.wikipedia.org/
i would imagine that this double-struck seatpost would be worth at least as much - but only if you can find the matching pieces to put together the rest of the ultra rare "double struck" grouppo from which it came ...
- Don (grin) Gillies
San Diego, CA