I think that there was a very minimal amount sold in the west, as the company went under very fast and there was fierce competition. I frequent western european fora and, really, noone ever speaks about these machines... Maybe we should put this question on RetroGamer's forum, since it gathers people from all over.
But, really, if what you ay is true, we have 73000 machines unaccounted for, and that's much more than several machines that are being discussed around...
However, just a thought: we discussed about the highest known serial number for 64's and 128's, but what are the LOWEST known numbers? It could be that numbering did NOT begin from 0000001...