The Germans began mfg the F2 model in March of '42, so by late May they probably had produced 200 or so, some of which headed to North Africa but the rest to the east front. So I am sure Milan's numbers are for K'42 as you guess, where there would have been more short barreled '75s than long - the southern Panzer Divs got first shipments of the new tanks at this point, in preparation for their summer offensive.