Landships II

I was going through my files and came across a group of photos of the WW1
vehicular camouflage that I saw on the old Marx tin toys. Remember those
schemes, with the bright colors separated by thick black outlines?
I often wondered if any of these paint jobs actually got over to Europe during the war. I have some photos that state they were taken in Europe and these show these paint schemes. But most of the photos I have seen of U.S. WW1 ground equipment in action always showed solid colors.

Futhermore. there are two relatively new books on the market that shows some of these U.S. schemes very clearly. They are published by Iconografix and are called Caterpillar military tractors Vol.1 and Vol.2. These have a few
photos in each issue of WW1 camoflage. The publisher can be accessed at:
http://www.iconografixinc.com/
I have a rare copy of the book commerating the war products made by the
American Car and Foundry Co. (published just after WW1). I just put the
color page from that book and the covers of both Cat books on photobucket.
There is a page from that book showing the colors (at least the colors after
being printed in a book that is 85 years old and copied and filtered through
my compUter and photobucket, etc. etc.)
You can see all three images at:
https://s187.photobucket.com/albums/x115/ssculptorphd/
Questions I have are these:
Assuming that the U.S. equipment that actually got overseas to Europe were still painted in these colorful schemes:
1) Were they overpainted one single dull color on the way to the front or at the front?
2) Or were they merely covered with mud and dirt and simply not washed. Was this done in WW1 in Europe on purpose or was this a natural by product of being driven through the very muddy areas of the war?
Anybody have any thoughts on the matter?