I'd get new spokes & nipples.
1. Loose spokes are a bad indicator of how much life your 47 year old spokes have.
2. Old parts just won't give you the "feel" when bringing up the tension.
I used to salvage wheels when I flipped bikes. I had more time than money.....
Even then, I'd use NEW nipples and wire brush the spoke threads. It still didn't come close to the SMOOTH, progressive "FEEL" as using new spokes & nipples.
One advantage you have, is that you still have "intact" spokes you can measure for the proper length.
Rear spokes may differ in length. Fronts will all be the same as each other, and MIGHT be the same length as your rear NDS spokes. Then again, it depends on what hubs you have. So, you need to measure 3 different spokes. 2 rear & 1 front.
I'd use a vise grips to "strip off" the old nipples. The right tension and it just cuts them open.
Last edited by Bill Kapaun; 06-15-19 at 11:46 AM.