For those new to changing your disc brakes on the front of your favorite car...your Bonneville of course (you big dummy!)...Here'* a quick pictogram that supplies you with the basic ability to tell what your pads are trying to tell you. Sorry that pic is so big, but I wanted the detail to be readable.
As you can see, many uneven disc pad wear problems are caused by caliper issues. As the cost of replacing the calipers is very small (less than $20/side where I live), it makes sense to replace the calipers if you suspect that they are causing a problem.
Also, while you are down there, take the extra five minutes to bleed the brake fluid and replace with clean and new. Your life may depend on it...
Remember that regular brake maintenance will save you money by preventing more major repairs.
Mike: 1997 SE w/ 183K, aka White Horse
, Gutted Airbox w/K&N, drilled 180* t-stat, tint all around, clear corners w/SilverStars, "PONTIAC" light up tail, PEMs, NGK TR55s