It may be a hoax, it may not be a hoax. The fact that no prototype pictures have shown up until now is highly suspect though, because history records that no prototype was ever even created...the project never got off the developer's drawing table because a final design could never be decided upon. Though both companies certainly had money to sink into frivolous prototypes, knowing the financial policies of both companies tells me immediately that such a prototype was unlikely to be created until a final design decision was made.
Knowing all of this information, I am leaning towards "hoax". But there is also the possibility that the knowledge we have available to us as the public might be wrong...it wouldn't be the first time and it won't be the last time, so it could also be legitimate. Still though, the fact that no prototype shots have ever appeared until now, 15+ years after the project was abandoned...well...