I think many would argue that simply being pro-life does not a social conservative make.
Others would argue that being pro life does a social conservative make...in fact most would. The left have been successful in marginalizing what it means to be socially conservative to just those who wish to have government "impose legislation". Social conservatism is also about the protection of the nuclear family and protection from legislation that they feel attacks that ideal-that is the side of social conservatism, that many libertarians, can and do take a stand. Fighting against social liberalism being legislated is where you will see votes from libertarian republicans like Paul-look at his voting record. Just saying "it's a states rights issue" is too simplistic- When discussing abortion, pro life libertarians, do see a Constitutional protection of life in the argument.