Getting a title in GA is no big deal.
If you can get the owner to request a new title, that would be easiest. Cost about $40 IIRC. Maybe you can pay that for the the old owner.
I bought an '86 and had no title. Note: 85 and earlier need no title to register in GA. Just a bill of sale.
To get a title and register it, you will need three things:
1. Have a cop fill out a VIN verification form T22B. Available on the DMV site.
2. Get a Title Bond from an insurance broker. This bond is for the value of the bike. If the original owner shows up with a title, this bond will pay them the value of the bike (and you will then have to pay the bond co.) Cost me $150 for the '86. Call your insurance agent, they may do title bonds or know one who does.
3. Bill of sale. You will need some paperwork. Type up a form stating the sale, the condition of the bike and the amount. It probably would be good to mention the stolen, recovery and loss of title on the bike on the bill of sale. Have both parties sign it. Having it notarized is not necessary, but good to do.
Take all 3 to the DMV with your proof of insurance and you can register it and apply for a title.
All the gory details and links to the documents are here: http://motor.etax.dor.ga.gov/motor/titles/titlebond.asp
$100 is great deal. Even if the engine is trashed, you can sell the parts on ebay and make $$$.
[edited for typos]