If there is not an open warrant on you for this case, this is an unusual situation.
You can't get this expunged because the case is not legally concluded. You can't apply for a pardon from the governor for the same reason.
To get rid of this you'd have to retain a lawyer and petition to get this case back on the calendar so that the judge can dismiss it. Then, once it's dismissed, you should be good to go with regard to a gun rights.
I see two potential grounds for a dismissal, but neither is something you can do for yourself. The first would be a dismissal on speedy trial
grounds. After 32 years unless you warranted on this case, the state has has well exceeded the time it should have to be ready to try this case. If for some reason that failed, the lawyer can also try to dismiss it in the interest of justice
. That is, a judge always has power under Equity to grant a petition to disimiss in the interest of justice even when the law doesn't provide for it, if it is necessary to prevent an injustice from occurring.
So with a particulary compelling argument -- and arguably closing a case that has been unaccountably open for 32 years is compelling -- this could succeed.
If there is a warrant, you will probably sooner or later have to go to Georgia to resolve it, but a lawyer can do the initial groundwork to lift the warrant, and if the complainant can't be located after all this time, the case will eventually be pitched.
If you don't know where to find a Georgia criminal lawyer who can help do this for you, you can call the Georgia State Bar Association's Lawyer Referral service.
They charge about $50 for the referral which includes a half hour free consultation with the lawyer which you can have over the phone if you don't want to go back to Georgia to meet him.