Regarding the Russian steel thing, I used to have a late 72, I was the 3rd owner and after buying discovered what a rust bucket it was. It had lived outside all it's life and had apparently been looked after and serviced yearly. This bus eventually failed it's MOT and I lost heart (although somebody did buy it and repair it, anyone know of MPF 781L).
Fast forward to 2002 and I bought a 71 that had by all accounts led a worse life although it was a very low mileage at nearly 26K compared to the 72 which had done about 115K. The difference underneath was amazing, apart from a bit of cab floor and rear corners the bus is still sporting it's original sills. I'm amazed.
So going back to the point, apparently VW did buy Russian steel in the 70's so some 72's maybe made from good metal and some not. Since learning this i've checked out many VW's of this time and have to say i've noticed a difference, maybe it's just me!