Hey Gary, you went ahead fast on it. As the resident antique VW buff, ( was a collector of OLD vw's in my 20's and early 30's) the body units were all the same color inside and out. Have crawled all over 3 different Kubelwagens and owned a 1947 beetle at one time. The interior and exterior on the militry stuff was either grey or sand depending on when it was built.
The other thing was that all the sheet metal on the engine and the air cleaner was black enamel from beginning to end off the factory assembly line. When repainted in the field it would have gotten some overspray (on the Kubelwagen) but most likely not on the schwimmer.
Oh, and the 3 differet Kubelwagens I got to look at, all had the engines replaced with one from a 60's model beetle. My '47 had a 36hp engine from a late 50's bug but I managed to find an original '47 engine with originalsheet metal. There was a LOT of little differences between the 3 time periods.
Should dig out my old ESCI 1/9 Kubelwagen and finish it. Have the tools and info now where I didn't back in the 80's.