That was the real deal. According to what I've learned, the man they called Mobey Dick was published in Club magazine sometimes in the very early 1970's as a response to the popularity of 18" black model Long Dong Silver. This was back in the era before computers, Adobe photoshop, Lucas' Star Wars special effects or anything sophisticated enough to produce realistic fakes.
This is a remarkable piece of adult film history. The Club magazine photographer, Rupert Daines, can be seen in this film holding what looks to be an old Hasselblad 500ELM 21/4" X 21/4" equipped with a standard 80mm Planar Carl Zeiss lens. I believe the original film format was Beta and subsequently transferred on to VHS. Perhaps some of the more senior members of lpsg.org in their fifties or older can supply more information. Thanks!