There is a lot of variation,  that is part of what makes German Ww2 armor  interesting,  it also gives you a measure of license in your builds as markings camo and other details varied not only in time period but from unit to unit as well.  I suggest finding some reference photos and working from that if you want to be sure that it is correct.   I have dozens of reference books I keep near my bench for that purpose.  The images of war series,  panzer wrecks  series ,  repairing Panzers vol 1 and 2   are all excellent,  but I suggest you start with  Sturmgeschutz  III on the battlefield,  world war two photobook series vol 2

 ISBN 978-963-89623-1-7