yes, I think that with that monitor, it's a great deal. I doubt it's a scam; if it is, it's a very unusual one. The picture is of the actual items, the seller accepts paypal, there are no external e mail addresses, the specs aren't cut and pasted from a website, the bidder's identities aren't kept secret, and there isn't one flat buy-it-now price with no option to bid. Perhaps most importantly, this just isn't the kind of item that typical ebay scammers use. They list much newer and more expensive things that will get many many searches (quad G5) and promise outrageous upgrades.
Of course, this could be a smarter scammer, but I think you just got a great deal. They really do exist on ebay, and in this case, I think the auction, for whatever reason, just didn't get as high as it should have.
Congrats and enjoy.