A black line underneath the eye is a trait of both species! It tends to fade, or is not fully expressed on very mature male GTs, but it is still a trait/characteristic of a GT, no less.
Your fish is a green terror, no doubt. The head and body shape is that of a green terror. It has the markings of a green terror----the typical mid-body blotch with the white horizontal stripes on each side of the blotch, as well as other traits. For whatever reason your GTs have very faded body coloration; maybe they haven't completely settled in yet (?).....for that reason it may not be as obvious to some that they are GTs.