This is true. There are a lot of guns, but a good chunk of gun owners own more than one firearm so the "average" is skewed. Look at the ones that have massive collections or the preppers for instance. Some owner collections have dozens or even hundreds of firearms.
There's also the clear assumption the OP photo makes that all of those owners are conservative and willing to fight for Texas. I have quite a few friends with firearms, on both sides of the aisle. In fact, most of the gun owners I know personally are Democrats. None of them would ever do anything to help Texas.