I'm not even certain what to call this camouflage scheme. Some people call it "the MASSTER scheme." MASSTER was a US Army organization for testing various materials and ideas, and this camouflage scheme was one the MASSTER test programs. I like to call it the "7th Army scheme" since it was only used on 7th Army units.
There is a page from the old AFV-G2 magazine which states the 7th Army scheme would be 30277 Sand for the base color, 30117 Earth Red , 34127 Green, and 37038 Black. However, 34127 Green was not one of the standard colors in the US Army inventory of camouflage paints, but 34151 Light Green was a standard color and is very similar to 34127, so 34151 Light Green needs to be strongly considered for the 7th Army scheme.
The AFV-G2 page states "Reference: VII. Corps Regulation 525-6, dated 1 June 1973." So, one may guess that the 7th Army scheme might have been in use from about 1973 until about 1977 when the four color MERDC scheme began to be used. For people who like numbers, estimate that Sand covered 30% of the vehicle, Earth Red covered 30%, Light Green covered 25% of the vehicle, and the remaining 15% would be black.
Most of the vehicles with the 7th Army scheme have black registration numbers, white bumper codes, the yellow bridge classification circle, and sometimes medium or large sized black star insignia.
An interesting photo set is found on this link.
M151's at the old inter-German border. (Photo US DOD)
Note the black star insignia and white bumper code. (Photo US DOD)
(Photo US DOD)
(Photo US DOD)
M551 Sheridan (Photo US DOD)
MIM-72 Chaparral in 7th Army camouflage. Note the road wheels are painted black which is not rare with the 7th Army scheme. (Photo US DOD)
M114A2 Again note the black star insignia and white bumper code. (Photo US DOD)
US Army 7th Corps Scheme
Sand, Earth Red, Light Green, and Black
(30277, 30117, 34151, 37038)
The US Army in South Korea briefly used a colorful three color camouflage scheme. Around 1967 and 1968 vehicles were painted with broad bands of Earth Yellow and Black over Olive Drab with each color covering about 1/3 of the vehicle. Apparently there was some pattern used when painting this scheme as vehicles from different units seem to have similar color patterns. White registration numbers and bumper codes were used with the scheme, the yellow bridge classification was always present, but US star insignia apparently are not used with the three color scheme.
US Army South Korea
Olive Drab, Earth Yellow, and Black
(34087, 30257, 37038)