Crappy parts store voltage regulators

Got 2 different regulators from advance auto and they kept over charging at 15.6v. I found and old wells regulator that says made in USA in the bottom of my spare parts drawer, sanded the edges for good ground threw it in and now car charges at a steady 14.3v.

The kicker is advance wont return it for my money back only exchange for another because it's an electrical part.
Were they grounded pretty good, i find over charging is due to a weak ground on the regulator, but with today's crap i would not be surprised if i was bad out of the box!