Many Rock Auto parts are shipped from Parts Authority warehouses
Parts Authority is clearly listed on the NGK page as an authorized seller. As previously mentioned, Rockauto generally ships their parts from Parts Authority.
For many years, I have looked at who actually ships items I've ordered from RA. I have never rec'd anything from a Parts Authority location. Almost all of our orders come from "Hahn Auto" in a suburb of Buffalo NY.
Buying from Rockauto, "we" have no input on what supplier they order/ship our orders from so just because Parts Authority is listed, you have no assurances otherwise....