If it was me ALL the old stuff inside would be replaced with modern components.
Crossover
Terminals
Wire
Add additional dampening if needed. But heck, that's the way I am.
Klipsch and Capacitors
I read a lot about replacing the caps in old Klipsch speakers. If a 40 year old pair of KG4s have never been used (new in box) would the caps need to be replaced? Just due to age?