Did you purchase from a Cadillac Dealer?
Before taking on the task for changing the brake pedal mechanism, it may be worth your time to visit that dealer to check if the bulletin pertains to your vehicle. If so, they may be obligated to fix it if the service was not done before it was initially sold.
If you purchased elsewhere, a Cadillac Dealer may be able to courtesy fix your car for free or a reduced price. It is a safety issue.