The lore of the wheel pinstripe always stirs up debate. Did ALL 3A's have them? Was it a dealer option? No one really knows for sure. What is certain, is that many original 3A's don't have pinstripes, and many do!
From the few photos of wheels I have seen, seems like all pinstripes were black. You can see in the photo that the pinstripe is centered on the bumpout in the rim.
The pinstripe measures about 3/16" wide and is clearly painted with a brush. With some sort of a jig, a steady hand, and a sign painters brush, you could easily paint you own pinstripes. You might even try a sign painter...