Doesn't matter. They are all of the same age. And were subject to all of the same stresses. 

So what your saying is, when I recap a tube type radio, or more likely, modern televisions, I only replace a few known suspect capacitors? Wrong... Try that with a Mitsubishi V26 DLP Chassis and see how far that gets ya. Change them all. When they are all that age, they all need changed. 

Granted some capacitors are of higher quality and last longer than others, I dont recommend leaving them behind. Same deal with vintage 70s/80s stereo gear, I recap it all. Sounds awesome and like brand new.