Back in the 70's and early 80's it was near impossible to get a carry permit. However if you were known to carry large sums of money (>$100) you could carry a handgun in the vehicle if traveling more than one county from your residence. Actually I think you had to have a county between your destination and home. So from Dallas County you would pass thru Tarrant and be OK in Parker co.
It was called the Bonafide Traveler law. You had to cross two county lines. But it did not keep you from being arrested till a judge can see you. Then you have to prove it. Each judge treats it differently. Ask me how I know.
After a couple of these run ins with the law in the 70s I said F it, and ditched the Super Blackhawk from my vehicle and just started concealed carrying illegally for the next 21 years until I got my CHL in 95/96.