Sure hope not - I have booked to camp there for a week in March (along with various other spots in Florida and S. Carolina!)
We have stayed around Savannah several times before at that time of year and had no problems at all.
Actually, I would check a few historical weather records (lots available on the internet) and be governed by that - for my part, if it appears from a review that there is much chance of a hard freeze, I would winterize just to be on the safe side, but if it just drops below freezing for a couple of hours overnight, that won't likely cause any problems.
Brian & Connie Mitchell
2005 Classic 30'
Hensley Arrow / Centramatics
2008 GMC Sierra SLT 2500HD,4x4,Crew Cab, Diesel, Leer cap.