Classic Parts of America has the 58-59 tail light housing. I deal with them a lot. They have full harnesses and they have just the tail light/rear harness and other harnesses/pigtails.
I would email them and ask them to provide part numbers of harnesses and pigtail harnesses that fit the housing they sell. Then order what you need. They are very good about a full refund especially after they answer your email and state what fits. Also, I PM'ed you.

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn