Oldtanker- At least among the Yanmars, "grey market" still has the old definition. There's an outfit, Hoye, that specializes in parts for them. Went on line to look for a manual, and they have it split into "Japan" and "US" models.
I remember when the grey markets started making it to our shores- dire predictions of no parts, inferior tractors, etc. Turns out the main difference is that the companies could build virtually the same tractor for their domestic markets for less money, because THEY DIDN'T HAVE TO CONFORM TO ALL THE *^$#% US REGULATIONS. As soon as some outfits started importing parts (which was legal), end of problem.