"only spare links would keep the paint"
as found here :
Of course spare track links as carried on the hull could be painted, we have many pics showing the tracks beeing camo'ed by the crew from the time when three tones camo was not factory applied ... or Pz IVs leaving the "depot" (sorry I can't remember the proper english or german word) with what looks like spare track links painted dark yellow, just as the tank was, showing a much darker shade underneath the coat of dark yellow ...
Remember this pic of StuGs (and a few Pz IIIs) at Alkett with brand new tracks painted what looks like a very dark color (I'd say black) but showing obvious traces of wear (natural metal) on the guide teeth and the track "sole" eventho they must've run only a couple of yards. From what I know the paint would go off very fast and the alloy used fo the track links would be covered with a thin coat of rust very fast too.