Although green was ordered the new base color for AFV's in December 1944, the practice probably didn't take place until weeks later. And with bombing interdictions of rail transport, parts, and assembly factories, few made their way to the fronts. There is a published pic, somewhere, of a group of very late Panther G's, knocked out/abandoned in the countryside (maybe Frenchy can help with this pic) allegedly in green and yellow. But in B/W photography, and on a bright sunny day, green could look very light like yellow (and vice versa) so sometimes colors can be mis-identified. But definitely some late production tanks were finished in overall green. As an after thought, some Panther G's of 1st SS in the Ardennes campaign had a lot of green and a lot less yellow and brown, so maybe these were some of the first in overall green.

To paraphrase the Panzer Colors book

I have seen a number of late war 251s that have a fairly standardised factory camo that is predominately green.Some are 2 colour(green/dark yellow) and others are tricolour.The factory camo looks hardedged but may be a very tight spray edge.Several are shown in Marek Solar's book on abandoned German vehicles in Czechoslovakia,and there are others in various issues of Panzerwrecks.Tom Jentz's book on the Panther says that after mid Sept.44 Panthers were ordered to be painted at the factory.Dunkelgelb was no longer to be the base colour,red oxide primer was.Dunkelgelb,Olivegrun and Rotbraun were to be painted sparingly in adloining patches over the red oxide primer.MNH received this order on Oct.31/44,so they may have started painting this scheme later than MAN and DB.The late war 2 colour Panthers appear to be MAN products.Hope this helps,Cheers...Murray McLennan