I'd guess not. Most of the aircraft in AH would have had an auto-rich position anyway, and that's what they would have used almost all the time. The other limitation to a mixture control is that we don't get all the clues in AH that we should. In RL, when I lean the mixture, I'm watching the EGT, but mostly feeling for the engine to get very smooth, then just before it starts getting rought again is peak EGT (and thus peak efficiency), so we run it just a tad rich of that point. But, the point here, is that we can't feel the engine in AH smooth out, and we don't have EGT anyway, so I'd say mixture management would have to be pretty tough.
blk (AT)