Not a good idea if you still have any hope of buying it from him. You'd have been better keeping him in the dark. After all, it's up to him to do the research if he's selling.
Just as it is yours to do, to know where you stand as potential buyer. "buyer beware" and all that.
Kev, you need to scroll down the link a fair bit - to a purple iridescent vase with metal work on it. I wouldn't say it's exactly the same, but very, very similar. I would imagine the actual design of the scrolls would change to fit the piece.
(But I do avoid all glass with bits of metal stuck to it. It can affect price in a way that I'm not prepared to accommodate. I'm not remotely interested in "precious" metals or designer-market-inflated price gemstones.)