According to the histories I read, the Il-10 had its combat introduction in Sep 1944 and 99 were produced before the end of 1944. Unless I miss my history, that was firmly in WWII and firmly against the German Luftwaffe. Most of the production was after WWII, to be sure, but unlike the P-51H, the Il-10 made combat against the Germans ... so it does not resemble a red herring OR the P-51H Mustang and F8F Bearcat that made the show but missed combat in WWII.
Were the early ones debugged and great airplane? No. But they were there and saw combat.
The P-39 certainly had it faults, but it was not a bad ground-attack airplane, especially at short ranges, which suited the Soviet VVS to a tee since the P-39s stayed low in Soviet service mostly, they ALSO weren't bad fighters down just above the heads of the troops. Under 10,000 feet, they were a decent match for most WWII fighters. They weren't too good above 15,000 feet, for sure. But many an Axis pilot was quite surprised to discover himself being shot down by an "inferior" fighter that he thought he could ignore. T'was not the wisest course to trifle with a well-flown P-39 down low.