I've heard this too. I once had a 1980 911 3.0SC which was a Japanese import to the UK. It was LHD and had been supplied new in Germany, but bought by a Japanese dealer for export. My understanding is that there was a degree of prestige in having a LHD car in Japan in those days, but also a real shortage of RHD stock, so dealers would import whatever specification of new cars that they could find. I think it wasn't till later in the 1980s that formal dealer networks for German car brands were formed in Japan, but I could be wrong.Someone said on Facebook that some owners often imported LHD cars into Japan as show of wealth (i.e. being able import etc) so likely this, rather than converted. I don't know the truth of this though!