I read somewhere (maybe on this site! - but may have been a usa site) that the 'g' was also included for bikes in the uk (which I suppose you could, at a stretch, say are European market) but I also read that they start with a '2' frame number whereas mine also starts with a '1' - cb750g-100**** with both 'first reg' and 'first reg in the uk' as the same date (03/78) so must be a uk bike.
I have to say there is a lot of contradictory info out there.