My own TU90 is stamped for both 7.62 and 9mm and would have come with 2 barrels and probably the spaced mag and a regular mag. I got it used with only the 9mm barrel and regular 7.62 mags. The mag worked fine but the barrel has some problems or posibly the link and pin but the gun would some times lockup half open and not eject the empty.It would take some pounding to get it come loose. It may have been the link pin which was not staked and could drift about. The barrel is made of fairly soft stainless and has nicks at the back of the chamber and the crown. I got a very nice blued 7.62 barrel with it's own link and pin and have never had another problem. The fit and finnishis not near as good as the Polish or Romanian and I did not like the wrap around grips as much but it is a good shooter.
Every day is an adventure of one sort or another, if you live, you learn.