Hi David - welcome to the forum!!!
Please post/attach pictures of your GSP Mustang. We love seeing pics of SSP Mustangs. Can you post a picture of your VIN sticker on the driver's door? We're here to help, so ask as many questions as you need to.
In terms of driving around in a marked antique police car, the rules vary by state and circumstances (i.e. check your state/local laws). Since you are in Georgia, then you'll have to be more careful in terms of covering your lights and GSP markings. You will also need to act responsably while driving the car to avoid drawing any unwanted attention to yourself.
Personally, I elected to not repaint my SSP in its original black and white colors. I have the markings on magnets for shows and parades, and I keep the lights disabled and covered while driving. That way I can operate the car with
less worry.