A good question though is how much do you have to change before you can legally drive it?
This guy here seems to believe that driving a police car with lights and even "911" and "Dodge Law Enforcement" is Ok as long as it doesn't say the word "Police" at which point it would be impersonating a police officer.
https://www.motorauthority.com/news/1100773_driving-a-police...
In this police forum where they are discussing the issue one person notes that in California driving anything that remotely looks like a police car is illegal, and another states that in Tennessee you can drive a police car if you feel like it. So state laws perhaps vary as to whether you have to remove the decals and/or repaint the whole thing before driving a decalled surplus acquisition.
https://forum.officer.com/forum/public-forums/general-law-en...