Bulldogs are a caliper style brake. They are like any other calipers and need a hole in your frame to mount to.

If your bike is newer, then it has U-Brake or Canti mounts on it and bulldogs are not compatible.

Also, while Bulldogs are one of the better caliper brakes, they are STILL caliper brakes and don't come close to the quality of 990's or Evolvers. Check what you need, or take a photo of your brake mounts and post it here if you are unsure of what type of brakes your frame needs.