I think so. I feel like too many human characteristics crept in to his later performances. This was his most convincing turn as a machine, the eye movements and the monotonous speech was spot on.
T2 was great too but the learning mode gave him greater license to creep in human elements.
Not only his best performance as The Terminator but his best performance, period.
There's nothing remotely convincing about his performance in T2. It's just Schwarzenegger playing The Terminator. Of course the mediocre script didn't help him. It makes zero sense that he would let those bikers live when they're attacking him. One of them even stabs him but of course, he'd become a big star playing heroes by then so we were never going to see him killing humans, even though later the film completely contradicts itself and has him on the brink of blowing someone's head off for far less so John can stop him in time and give him a good telling off. It's complete nonsense. And don't get me started on the Bad To The Bone scene. People rightfully make fun of T3 but the poor writing and wink wink at the audience already started with T2.
This is the only one where Schwarzenegger was convincing as a cyborg.