Opinions on using original wiring harness in restoration

[chewychevy67]

I am doing a very thorough restoration on my 67 gmc. I have all the original wiring and it is all unmolested and looks like it's in decent shape. Now that being said it's 40 years old. My once is some of the new harnesses have modification for newer stuff built in like internal regulators and I want to keep my truck completely stock wiring. Am I looking for trouble reusing my stock harness. I did get new wiring for the tail lights and that intermediate harness from the firewall and some accessory stuff that are stand alones. Any opinions?