Improvised Weapon Mastery & Grappling Hook

Quick question: Grappling Hook is classified, normally, as a tool, however, there is an option in my Pirates of the Inner Sea to actually become proficient with it via Exotic Weapon Proficiency.

If I were to do this, would it negate the bonuses from Improvised Weapon Mastery, since I'm now proficient with it?

Yes.

Okay, thanks.