He's not buying a FR bridge; it's a Schaller "Vintage Strat Replacement". The bushings might be the same, but I wouldn't want to chance it. If the internal threads aren't the same, then he'd have to pull them to install the right ones, which he apparently isn't comfortable doing in the first place. Even if they did work, what to do with spare bushings? Type of thing that goes into the Drawer of Misfit Parts until a year later when you look at them and wonder "why in the hell did I buy a set of bushings all by themselves?"