It's a poncho, lots of Marines carried a poncho this way when not carrying packs and stuff. It was also carried this way in boot camp sometimes, and this is up through the beginning of the vietnam war when we were still using WWII "782 gear" (packs,tents,poncho's,cartridge belts,suspenders that kind of stuff) Colors? The usuall olive drab, but kind of semi-gloss as it was a rubberized or plasticized fabric. Add dirt and dust too, we used them for everything, ground sheet, shelter half (tents were heavyer and not as waterproof), sun shade (fade the O.D. color), blanket and oh yeah poncho.
happy modeling! oh, and when you wrap it around you cartridge belt it won't be perfectly folded either. made a seat cushin too.
G.L.