As stated above, the Panzer grey was used until February of 1943. After this vehicles were painted dark yellow and red-brown and dark green concentrates issued to the panzer units. The beauty of the German camo schemes is they were so varied, almost any pattern of the dark yellow base with red-brown and/or dark green overspray would be appropriate and realistic, as it was up to the crews to determine the patterns of camouflage. There is some documentation regarding some units formed near the end of the war which were painted in nearly identical camo patterns; but this would be a rare event. Softskins and halftracks were frequently overpainted with brushed patterns, as only tanks had built-in compressors for spray painting. The dark green and red-brown paints came in 2Kg cans in paste form; they were diluted with whatever was on hand: gasoline, oil, mineral spirits, even water. Therefore the variance in color was enormous, and we cannot say with any degree of certainty (or anal-retentiveness) what was a "right" color. Keep in mind a brushed-on color would likely be darker in appearance than a sprayed-on color as well. On occasion, crews even applied the pastes to their vehicles right out of the can; this would tend to make the red-brown almost a chocolate color, and the dark green appear nearly black. Weathering also had a huge effect on paints; colors diluted with water would be far less permanent than those diluted with gasoline or oil. The sun also faded colors quickly in summer.
In answer to your earlier question: I personally don't think Panzer Grey would be a likely color for this vehicle (251/22), as it was produced in 1944; If you are going to depict it as taking part in the Italian campaign during 1944 it would be in dark yellow base color. I'm not sure if this particular halftrack was produced toward the end of the war, as Germany was concentrating on building tanks, so it's seems unlikely you would see it in Panzer Grey.
Hope this helps; good luck with your project and let us see the pics when you're done!
And I hope everyone had a Happy Thanksgiving!
Ne cede malis (Latin: Yield not to misfortune)