If you can't prove something is true but it could greatly increase the value of a peice if you make a connection between it and someone important, wealthy or well known, then a good technique is to infer the connection while at the same time raising doubts about it.

This covers you both ways.

You sow the seed you wish to sow, and no one can call your bluff.

This tactic works just as well for the weekly auctioneer as the top end specialist.

As always, caveat emptor.