M2? Wasn't that the development platform ... for 3DO I think? That was supposed to be their big badass new console about 5 years ago, before their hardware division went bunk and they went to software only.
Hell ... I think I may even have a game mag with some info on it ... I remember it back when that one game Shiny was working on with a little cherubim as the main character and you'd possess various other characters from the game ...
Yeah, here it is, Next Generation, Sept. 1997
"M2: The end of the console that never was"
Apparently dev kits made it to a few 3rd parties as far back as July 1995... so it may be possible he actually had one.
As for a PS2 dev kit, they had released one a few years back, for $700+ that was a development platform, but it wasn't the actual dev kit they send to 2nd and 3rd parties. I think it was based on linux, and was mainly for programming oldschool style games, as all the developement took place on the system (ie: no (or severly limited) 3d modeling/rendering capabilities) I'm guessing that's probably what he was selling