In the 60s I imagine stuff like that was much more popular. That might get you arrested in some states and situations.
We had gun racks in the back windows of our trucks. The same trucks we drove to school. No issues at all.
The difference now is the people. A lot more low quality individuals out there today. They would break in to your vehicle and steal your guns. You can still carry them, you just have to conceal them in your truck or other vehicle.
My guns at home are in my safes. All except a few around the house for security. My vehicles still have guns in them.... just not in plain sight.