Our DDS office was as casual as any other "business" would seem. Ours doesn't have the greeters, but then our office doesn't see the traffic that yours probably sees. It is also right next door to our local GSP Post. I would expect they have some means of security in place.
I also was about to leave my "pea shooter" in the truck when I realize there were no metal detectors or security.....so, I stayed armed.
As of now, the only two buildings in our county with metal detectors and armed sentries is the Courthouse and County Administration building.
This year, I think I'll pay tag taxes online and bypass having to unload everything, except a flashlight and the knife hanging around my neck that I 'forget' about..... the SO deputy manning the detector knows me by now and knows I have metal in my body, so when the thing beeps, he just asks if I left everything in the truck (the first time we met, I had to make two trips back to my truck to be declared "clean enough" to enter).