I would call the USFS office closest to the point on the map.
It is their job to assist in interpretation of their map!
Sounds like one of those "map details" that is either left over or a included as a courtesy.
While the outfitter may be licensed for the area and might even have been granted exclusive rights to the camp spot, they shouldn't have any "exclusive" rights to the hunting in the area if it is not leased. (BLM possibly; USFS doubtful)
Even when a BLM property is "landlocked" by private holdings you could hunt it if could figure out a way to get in there.
One of these days I'm going to hire a helicopter to drop me on a square mile in Colorado just to make that point to the guy who is charging trespass for public land access.
The jerk charging the trespass fee to grant access to public property wouldn't agree but they would be wrong.
Feel free to PM me with the Lat/Lon or specific landmarks that will get me on it and I'll give it a look using a program I use that has some pretty good map layers.