I would tend to agree, if I had ever seen an M48A. But, it seems logical enough. Yugoslavia's arms making equipment had been wrecked, ruined, or hauled away and most likely that ran just as true for the skilled personnel that had worked in it before the Nazis came.
As an ex machinist I can say that on average it takes at least a year, sometimes 2 to train up a machinist to be reasonably experienced in all around operations. Of course, a machine operator takes only about 6 months.
Figure too, the drawings and knowledge of many of the technical tasks and details, such as tolerances and heat treating, something in particular they had trouble with getting right (never fear. They figured it out.)
