Fint Kemper -
Most old aluminum nocks were turned down from solid rod stock and were drilled with a parallel hole for the shaft.
I've owned dozens of old arrows with aluminum nocks over the years, but don't know of anyone who was molding aluminum arrow nocks.
There were many different molded bow nocks from aluminum or other metals dating back to the 1880s.
Many of the old arrows with aluminum nocks really look cool.
You would probably find that there is a market if you were to sell aluminum nocks with a tapered hole. I don't believe the old style with a parallel hole would sell very well.