Thanks... thats useful info. So a limitation of the mould making, rather than a track style I didn't know about?
I will probably just treat them as all steel and weather more heavily than I usually do.
And good catch on the M10 - thanks. Think I will shave off the grousers that are on the racks, as I am building a late-war SA 6th Armoured Div Achilles from the kit and most of the photos show them with steel tracks, and racks used to stow other clutter...