I'm confused about the different versions of the Wehrmacht leFH18 cannon, as originally I thought there were two and since found out there were three. The leFH18m version as sold by AFV Club includes the later wood-spoked "wagon wheels", and the directions show only how to build with those, but when did that version replace the older steel-pressed ones? Or did the kit designers get it wrong?

No Tom, AFV Club got it right. The version of the LeFH18M they offer is a late war one with the pressed steel wheels replaced by strategically less important wood. Strictly speaking there would really be 4 versions, viz the pre-war original version without muzzlebrake & with steel wheels; the 1941 - on version with muzzlebrake & steel wheels; the late war version with wooden wheels; & finally the LFH18/40, which had the modified Pak 40 carriage. There are other sub-versions, eg different designs of muzzlebrake, but those are the basic four. AFV Club offer 3 of the four out of the box, the missing one (ie the muzzlebrake/steel wheel option) is easily possible by mixing kits (they may even include the steel wheels, I don't know). Interestingly, despite the chopping & changing with the carriage, the ordnance itself remained largely the same. Strangely, only one "native" SP version was produced, the Wespe (some were mounted on French tank chassis, but not in really large numbers). If you want a real "bitsa" you could try the late war 75mm for infantry divisions, which took the 18/40 carriage (which you remember came from the Pak 40), & once again mounted a 75mm on it, which was based on the Pak 40, so what you got in effect was an anti-tank gun with the ability for high angle fire like a howitzer! It was called the 7M/85 or something similar.