I just bought 6 of the PF64s from Rockauto, and they arrived in a bulk box with AC Delco Made in USA Detroit, MI markings indicating it was for a pack of 12. The weird part is that none of the filters are wrapped or in individual boxes. It was just a box of 6 loose filters. Everything seems to indicate they are legit AC Delco PF64's and it is RockAuto.
They are for the girlfriend's 2015 Malibu 2.0L, which burns about 3-4 qt of oil every 7500 miles.