Well there are rumors about it. Ive heard about it once or twice. As to whether or not this one is real, its virtually impossible to tell. And letting it go for like 100 pounds, or around $250... I mean, the only recording in existence of a Queen song never released (in that form at least) would go for a bit more I think... I hope...
Yes, this is indeed a genuine item.
I too own one.
Mine is identical - but it also has a white circular self-adhesive label/sticker promo club mix on one side.
I think it cost me around £20 at the time of release (ie mid 1980's).
The music is the just regular 12" version though - nothing special there I'm afraid.