I make no such assumption. Could this be a sham auction? Sure. However, there are always fees associated with Ebay and jacking up this auction to $1500 will have cost the seller a significant amount of money. For what purpose somebody would do this in the vintage airgun market escapes me, however.
Of course maybe this guy found a bunch of NOS 342 in a warehouse and decided to try and jackup the vintage airgun market. If so, we'll see some more come out of the woodwork. As it is, like I'm sure a few others have thought, do I still have that boxed 342 in the collection? Had one at some point but will have to start digging to see if it is still hanging around.
And, like I said before, I've always felt that the prices associated with vintage airguns on the whole was suppressed by a restricted market. A vigorous vintage airgun market on Ebay, just might kick prices up to levels never before imagined. Note that airgun sales have been allowed on Ebay only for the last year or so. We'll see what happens.