Dan, since I am not a native of DFW area, someone else might have more details. But, this is what I heard:
MAL was the initials for what I think was Model Aircraft Labs. It was an old, old hobby shop in Irving, TX. I think the shop first opened around 1947. By the time I got back into the hobby (late 90s) the shop was run by a father-son team. Dad passed away and the son took over. I am not sure if the son is still living or not. I think they closed not long after my last visit. I am guessing the shop closed a few years ago but not sure exactly when.
On one of my visits, the son told me that when he was a kid, they could walk out the door of the shop and there was an open field to fly on. Of course, you can imagine what the area looks like now.