Like Ken says, in that time period they would not have been in MERDC scheme. Most US vehicles would have been in olive drab still, except those in 7th Army in Germany, which would have been in MASSTER scheme. If so, I can certainly see why you would confuse it for MERDC desert: MASSTER was basically a light sand colour with large red-brown and green patches, and smaller black ones.
See this thread for more information on it:
But even more than with MERDC, vehicles generally did not conform to any published camouflage schemes. Which is handy for the modeller, of course 