I think there might be some relevance of area level vs loot from lockers, but not sure
I know of an area that has a LOT more lockboxes than any area near boneyard, thus more loot, the quality of loot is about the same though, it might be harder near SF due to bounty hunters and such but you could try.
I've opened a ton of lockboxes, BPs are pretty rare, and finding a specific BP is even rarer, so the CA BP is gonna be hard if not impossible. maybe a straight week of farming every day in a good spot might help but i can maybe find 2-3 BPs if i devote a whole day to lockerhunting