Hmmmm.....In all my reference books, when USMC tanks are shown they all do carry the "yellow" lettering. But getting info about colours can be a real pain. I have no books specifically on Pershings but will be doing mine as it appeared in Europe, preferably with the 9 AD.
I've gone through all the resources I can find on the internet, and the only WWII Pershing tank I can clearly "read" the markings on belonged to 3 AD [>:] (I really wish someone would do a "walkaround" of John Grimball's "Bridge at Remagen" tank from the Wright Museum in Wolfeboro NH. )
(My personal "nightmare" involves finding the correct markings for KT #104, of the 1. Kompanie, s.SS.PzAbt 501, in the Ardennes. In all "actual" photos I have seen I cannot make out ANY markings, neither national crosses OR numbers, so how a tank was "identified" beats me [

] )
I gotta agree with pattoncommander that if a Museum is going to "redo" and preserve pieces of History, it should as "accurate" as possible. Otherwise what's the point of the "preservation" ? Endless frustration for modellers who faithfully copy what they "see" only to find out later they've "done it all wrong" ! And it doesn;t just apply to "tanks", either..... !
Your Pershing's "Paint Coat" looks great and far better than mine will, if its any consolation....