Chef Skillet came out in the '70s as BSR explored the capabilities of DISA automation. In general I've found BSR markings of that era to be very inconsistent; you may have "marking A", "marking B", "marking A & B", or no marking.
Mine has "Made in USA" across the top backside. it has a relatively crudely ground smooth cooking surface that left grinding swirls but is better than unground. It is fairly light weight, capable of easy tossing instead of turning.
Lodge ended up owning the BSR patterns after BSR folded. They make this Chef Skillet to this day, you can find it at Walmart. The modern Lodge version at Walmart appears the same but is significantly heavier in feel. And has no ground smooth cooking surface.
What you have IDK but hopefully this helps. It's either BSR or Lodge; go check out a modern Lodge model and see if there's any differences in weight and finish.