It says “ Vua chiến trường” which is Vietnamese for ‘King of the Battlefield’.
Yep, ARVN M107 captured during Lam Son 719. It still exists, I’ve seen it up close at the war museum in Hanoi. Can’t find a better pic, the courtyard area is quite crowded with various bits of kit but of you look carefully you can make it out behind the Il-14 transport plane.