Yes, we teach social skills all the time by being guests, hosts, writing thank you notes, speaking with new people, etc. It's just a matter of modeling and talking about it. But, look around NObody is perfect, and I'm talking about adults. Is a life long process and not something most people master in childhood.
When I worry (and I do) I try to keep my experience as a teacher in mind. There is a whole spectrum of everything. For every quirk one of my kids has, I can name ten kids who are worse and go to school. When I see them with their PS peers, I worry that they don't know who Justin Beiber is, but then I'm thankful for the other characteristics they don't have because of the influence of that whole 10 year old girl culture.
Just keep plugging away at it! The world needs all kinds of people. :)