You raise some good points with that bumper isolator. It reminded me that I pulled a pair of those off of a 68 LeMans for the rear bumper. They're hefty pieces of rubber and they are still in perfect condition. It's been 15 years ago and they're still on my car today.
I also have a throttle stop solenoid off of the same car and the rubber boots on it are still perfect.
I only cleaned it up. No cracks or tears.
