I hate to break this to you guys, but the video is a fake. It was made by the same guy that made the Long Dong Silver vids, and both he and Moby Dick appeared (and disappeared) at the same time. The film maker has a cameo role in the video and appeared on British TV years after the event and discussed in detail how it was done, even going to the trouble of bringing one of Long Dong's prosthetic cocks out of retirement.
He used a latex prosthetics and expert make-up artists to create the cocks, with less attention to detail on the video shots but special attention given to the quality of the make-up in the stills and magazine shots.
I'm afraid that saying it wasn't possible to obtain that quality of deception before photoshop is like claiming that John Hurt actually had to get neurofibromatosis before he played Joseph Merrick in the The Elephant Man, or that Mark Wahlberg had to grow a foot long cock to star in Boogie Nights. Movie studios have been producing those kinds of effects since the 1920's, it's no big deal to them.
cheers
Dillon