It is not known if this Space Marine was ever intended for release, or if it was simply an in-house cast. The front of the tab is labelled "MARINE" and the rear "GW 1987". I've looked through my back catalogue of Rogue Trader era Space Marines and I can't find any obvious candidate for a donor figure, so it's possible that this is a completely new sculpt. If anyone spots a potential donor then please leave a message. Slaanesh had their Noise Marines - is there anything in the fluff of the period that mentions Space Marines wielding guitars? Not that I'm aware of.
So here he is: pretty crude, but great fun!