Thanks, phos!!
The Israeli connection hypothesis has some merit. And it makes a lot of sense. Although, that's quite a long time to hold on to so many type54's, no?
I've heard Albania suggested as well. But if that were true, wouldn't we have seen them before now? Or might the costs of trigger modifications have been the kind of thing that drove importers away from the 54-- you know because the type56's were a much simpler endeavor. No mods. No cleaning. Just sort, pack and ship.