SARAH BRADY, whose husband was shot in the head in the 1981 attempt on President Reagan's life, had more than enough reason -- and plenty of good arguments -- to appeal to Virginia legislators recently for at least some moderate controls on the flow of firearms in the Old Dominion. But if the deaf ears of those lawmakers were at all indicative of what response may be forthcoming from the General Assembly, neither Mrs. Brady nor the top law enforcement organizations in the country can expect any help in the coming session. "I don't anticipate any major initiatives" said Del. Clifton A. Woodrum of Roanoke, chairman of a subcommittee of the State Crime Commission, which supposedly studied proposals for changes in gun statutes.

That's no surprise, given the attitude of the majority at this year's session, which enacted a measure barring localities from adopting any controls unless specifically authorized by the General Assembly. Gov. Baliles didn't do a thing to stop this anti-home rule measure, either, except to ask the crime commission to study implications of new armor-piercing ammunition, plastic firearms and other "related threats" to police and the public.

One of the deadliest threats to police -- ask any of the authorities who have been campaigning for more protection against over-the-counter sales of handguns and other deadly equipment -- is the absence of serious waiting periods for handgun purchases.

Mrs. Brady, who is vice chairman of Handgun Control, Inc., said in a statement presented by a representative of the organization, "Virginia is considered a gunrunner's haven by law enforcement authorities. . . . I ask you to take a step that will finally begin to make it possible to keep handguns out of the wrong hands." But for now, at least, Virginia's politicians don't seem to care. They would rather give lip service to law and order than give law enforcement authorities the protection they seek to do the job effectively