I've had the Russain trucks for a while as I bought them at Bovy last year. It's a reminder to myself that I really ought to take my glasses with me to the B&B and check things properly before buying. Superficially they looked OK but the models were covered in thick coat of spray paint that hid a previous bad paint and construction faults. Once stripped of the old paint the models had to be repaired before repainting, luckily I had some suitable spare parts. The Katyusha took two attempts before I got it looking OK, it's reinforced with steel wire.
The 45mm AT guns are from Plastic Soldier and were no problem at all. All the trucks and guns were painted my Russian green and then stippled/drybrushed white