I recently purchased a 1990 TC. I checked the spare tire for it's condition.
While it looked OK, I also checked the production date.
The result was that it was made in June, 1988.
Since I also have another collector car, I have had experience with old tires.
There is NO manufacturer that6 recommends using a tire over 10 years old.
Since the newest TC is over 27 years old, we should not be use an original spare tire with our cars.
I have made the decision to keep a can of flat tire repair in the car and NEVER use the old tire.
An old tire whether on the road or a spare (on the car) is a time bomb.