I'm not a huge fan of black spokes, but for those wheels I would try to avoid the clash between polished silver spokes and the satin finish on the hubs.
I don't re-use spokes if they've done good miles, are aged visibly or chronologically, or just unknown. Except as spares. Seeing as you are re-rimmimg from a spares pile with the complement required, it seems a no brainer.