sorry, i missed this. i would say yes, it is either diamond or sk. those look to be the heavy duty cutters. for a time, diamond made pliers for sk. i have seen the sk slip joint pliers with the tell tale diamond casting in the handle.
there were lots of cheaper pliers with lighter green handles but they were pretty easy to pick out. i don't know of any other brands that used that dark green color. klein has used a lot of colors but i don't recall seeing that green.