I know this might sound like a weird question, but bear with me here. I mean, when you think of the usual ASD/HFA person who comes off as somewhat robotic or forced or what have you, and they lack social sense that's one thing - but if someone's more boisterous and exuberant and lacks social sense, you tend to think of them as more NT (and I've tried the boisterous and exuberant thing at age 21, it didn't work so well ).
By that token, it IS possible to conceive of NTs who lack social graces. The closest example I can think of in popular culture is Steven Stifler, he of the American Pie movies series. The character completely lacked social graces, and seemed to be oblivious to social sensitivities or norms in whatever he did. He wasn't a sociopath or a sadist or anything of the sort, but he was just downright juvenile, with a lower emotional IQ and age. Yet the funny thing is, we don't label such people as being "socially inept" - must be a Western cultural bias or something. Leave you to ponder that one