Perhaps...?
I'm NT and I've spoken with a fair sum of people—unfortunately—and I don't think I was ever able to tell that any of them were ND unless it was so severe that it were borderline disability. I have, however, become extremely frustrated with people in situations where I believed them incompetent. I could go on and on about the amount of times I've had to deal with some food service zoomer getting my order wrong six times in a row despite me giving them very clear instructions.
It's moments like those where I cannot help but wonder if the person is somehow even more retarded than I am, because how are you THAT bad at understanding what I've asked of you?
But I've never thought of them as ND, because they seem like the kind of people who would socially mog me—rather, I always assumed them, as I said, 'incompetent.' It seems like they just don't care about their job or basic etiquette more than anything...