I was never tested or accelerated as a kid - I was just a horrible misfit and was constantly stressed as a result. I got tested in my late 20s and scored in the HG range (150+).

My DS was tested but an IQ couldn't be calculated because the range between high and low was too broad. Currently he scores way ahead of age level in some achievement areas and below in others (a classic 2e thing). I have NO idea if he's NT, MG, HG... not a clue. Based on his capacity for abstract thinking and the speed at which he learns, though, I doubt very much that he's NT.

My DD has had very similar behaviours and milestones as me, so I estimate she could be HG. The only testing she's had was in math in grade 2, in which she scored about 3 years ahead.

So... yes for me, no for them...