Yeah, you don't just walk into the tank store and order up a Panther, though in this day and age I find it upsetting that we can't.
I worded it wrong...I mean obviously they would have been a common sight, and what I'm saying is that maybe he saw a bunch of them after the war awaiting their fate and made a deal with whomever was in charge to take one of them off their hands.
As for tank stores, well, I wouldn't be surprised if in some deep black market somewhere you could probably order some cold war era tanks.