When we rewired and re-rigged our '88 spar a couple years ago, all (!) of the OEM wiring was questionable. The lenses, bases, and etc on the old fixtures were nearly beyond repair or servicing. Lesson was that this stuff has a design life, and we were beyond it.
Please do this work while it's relatively cheap and easy ..... while the spar is down!
Replace the old coax, too.
We replaced all the sheaves at the top, also.
Ray's advice about running tag lines is spot on, as well.