Concur re: the legalities, and it only being more valuable to people in places where state laws that piggybacked on the federal AWB are still in effect, or other such statutes are in force.
However, if it is a Springfield Armory M1A, it means it is probably from a time when their products included a higher proportion of USGI parts than they do now. This may cause it to command a higher price than another used gun to someone in the know. Or, it may not. One way or the other, don't expect the gun to be worth a whole lot of money, as compared to other M1As.
Mike