Pete, when I had my new Etec fitted part of the deal i struck with the dealer that supplied and fitted the Etec was to stick my old engine on a standin their workshop for one week while I listed it on eBay.
They also agreed to run it on muffs for the winning bidder to check it.
If the winning bidder wanted the engine rigged they could also have done that for him.
I sold a 1996 engine albeit in good condition with unknown hours for £1800 via ebay. I doubt a dealer would have offered me half that on a trade in.