No, but I have replaced my backplate with a newer batch of backplate and it hasn’t crack yet so might be they upgraded the durability. I would definitely recommend the VFC MP7 over the MP9 as it is much much better as a platform.
Unfortunately, I never gotten to use it in the 40s as I live in sunny california. But if you keep the magazines heated or just near your body heat, I’m sure it will shoot just fine, definitely good in semi but full auto mag dumps are probably a no go.