Since I paid a whopping $0 for mine, I decided to keep it..... It has always worked fine for me.
So the controller goes up to 14.2V (not 14.6 as I previously speculated), and the audible alarm goes off for a charging voltage > 14.65V per the NL documentation. I did a bit more reading and poking around the interwebs, and it seems that this is not uncommon for initial starting and cold starting scenarios, but shouldn't last more than a few minutes.
1976 FJ40 - green and mostly stock
1996 FZJ80 - not so stock