Likely, it's VHF-high (154.680/154.800). But, where in Georgia did you see them?
GSP has long since abandoned the 42 MHz frequencies.
If the antenna was 52" or 104" length, it's likely CB for interstate traffic, etc.
If were 18-40+" tall, it's likely VHF-high band (148-174 MHz).
Due to budget cuts GSP is now only buying Crown Vics and they have abandoned the expensive blue on silver paint scheme for all new cars. All new GSP vehicles will be a solid color with orange lettering. I drove through a DUI check operated by GSP in Atlanta on Jan 1, they had 3 new all black crown vics out there.
I have seen in a number of locations around Georgia police cars are becoming solid black. I've seen in several north Georgia communities, Savannah and around metro ATL. So is black the new trend in GA?
GSP now has several Troopers throughout Ga. assigned to DMV and are doing nothing but checking truck regs. I have a friend that is assigned to that detail. You will find that those have CB radios in them since their scope of interest is trucks they have CBs. Thinking the units you saw may be from that unit, there is no different marking on the cars that I have seen but they will have a CB antenna on them. Most of the regular troopers dont care about a CB in unit anymore, got too much else to fool with.
I saw yesterday a GSP Canine unit it was a black Tahoe with orange lettering looked good