I just picked up 3 ACDelco PF-52's from Advance Auto for $2.98 each. Didn't notice till I got home but the boxes and the filters just say AC Delco and do not have the Duraguard name anywhere. The last 3 I picked at PepBoys had the Duragurd name on them.The 8 digit product code matches the Duraguard box ( I keep the box tops for warranty ). Is it possible these are old ones or am I worrying over nothing? Like that never happens here.