This oil is presumably labeled with the dexos 1 logo.
Dexos 1 is barely a spit of a wad upwind beyond API SN, so I'm not sure that matters.
It's not as though GM would sell anything less than a top quality product under one of their brand labels.
Well, most of the time, but the bad stuff was all "old GM", right?
Four bucks a quart is not a good deal on a blend oil that's probably nothing special, unless you really prefer quarts to jugs.
If there isn't a splashy advertising campaign how will the general public know if it's any good, or not? This is especially true if it's not on a NASCAR banner. Everyone knows that the best oil has the best advertising and appears on the best race cars.