Rob
I have removed small sections of wiring from my BJ7 and found the insulation to be a tad brittle, in particular the tails to the head lamps, and the wiring down the steering column these I renew as I go around the car. I have also noticed how stiff the wiring feels running along the chassis from front to back of the car, that is still in position but I have new wires to replace them at some time.
I think that it would be wiser to go with new. This is my personal opinion.
Bob