If it is like most other store label brand oils, it is probably done for them by Warren Oil. It is as good of quality of oil as most any name brand on the shelf. Warren is a very reputable blender with a long track record of putting out quality oils. It will meet all the specs that they list on the jug just fine.
What many folks fail to understand, is that there are only a couple of refineries that make the bulk of base oil for the entire N. American market. And there are a couple of additive makers that put together the additive packages in the oils. Most all brands and no-names get their base oil and additive packages from these suppliers. Shell has the largest conventional Group II / II+ base oil refinery in the U.S. at Port Arthur, TX. Lubrizol and Infineum make most of the additive packages for the N. American market. Blenders like Warren just mix it together for someone, slap on a store label, and ship it out. Even high brow oils like Amsoil get their additive packages from Infineum and Lubrizol, as do all of the other name brands. I use Schaeffer brand oils and greases, the oldest oil and lube maker in the U.S., since 1839, and they get their base oil from other refiners and their additive packages from the same makers as everyone else. The blend might be tweaked a little to give it some characteristic that the blender wants, but even using base formulas, it will meet the current motor oil industry standards. Schaeffer does like to boost their stuff a little with more moly and some proprietary friction reducer they call Penetro. Other brands tweak the add packs a little in similar fashion.
Get some of the Rural King and try it out and see if it doesn't do a great job.