Yes to the P-39N.
As for the P-63A, even declassified Russian sources do not point to it being used untill the very end of the war in the ETO. Most of them were kept in the Far East for the coming invasion of Japan.
In early May 1945 9GIAD which was Pokryshkins unit, received some 36 of them but decided not to bother converting to it as it was deemed a waste of time. 5GIAD also received the P-63s but did not convert to them for the same reason.
This isnt surprising in that there was virtually no air combat with the LW in the last weeks of the war, almost all VVS sorties were ground attack, recon, ect. Air combat as a priority just wasnt there any more, and you didnt need new P-63s to strafe retreating German Volks infantry, and horse drawn carts.
They saw very limited action against the Japanese for a few weeks in August 1945, scoring 2 kills.
Had the atomic bomb not been dropped, perhaps it would have seen its day, but like the F8F Bearcat, its chance to do any real air combat was snuffed out. Fortunes of war.
