No, you can have both. I think that if the brake is US made no other modifications would be needed (aside from the 6 needed parts for the pistol grip), but I've seen some troubles in this department when using an imported brake. I do not know if that part counts in the parts count, but I don't think so. Once again, I'm not much help. You'll probably see a good answer from a regular here sometime in the morning. I'd like to refine my parts count knowlege too, so I'll be awaiting this answer like you. I'm fairly certain that 6 parts will allow you to put on a pistol grip. I believe that the FCG is 3 parts, piston is 1, and furniture is 2, and I may be wrong about the brake not counting, hell I might be compleetly off on what parts count, but hopefully this will be something to chew on till tomorrow..