That must've been a Walmart, they sell guns in over 2300 stores across the US, and 175 of them in Texas have a federal firearms license from the ATF. But it would be extremely unusual to see it on the same aisle as beer and wine (Texas doesn't sell liquor in grocery stores), for reasons of space: guns are stored in locked glass cases near a desk where an employee can conduct the federally-required background check with the FBI and post the state-required warnings about safe storage of firearms. That takes a full aisle.
Meanwhile, shelf space for beer and wine (which in Texas are usually 2 aisles when you include the refrigerated cases) is hotly sought after by the beer and wine distributors (Texas has a three-tier system for beer and wine), so it would be difficult for a store to give away even an inch of shelf space to something else in that area, which is often near the back of the grocery section of the store.
Usually the guns are in the sporting goods area, between the camping gear and the automotive section....
