I don't know about Wally World, but in auto parts stores I'm still seeing 5w-30 that says on the back "suitable for ILSAC GF-4", right along side of bottles of 5w-20 that say "ILSAC GF-4". I'm assuming two things from this. If I'm wrong, feel free to correct me.
My first assumption is that although it's been some time since Katrina, inventories of the "substitute" oil are still on the shelves. No telling how long it will be before they are sold. Only then will stores order more, which (by now) will hopefully mean the normal formulation.
My second assumption is that Mobil is the only company which is honest enough to indicate that the "post Katrina oil" is not the normal formulation. I'll bet plenty of other oils are not the usual formulation after Katrina, but they don't say so, since by law they're not compelled to.