As a general rule the <3" dia. (smaller) Champs like ST/STP are not ecore. Larger diameter (>3" dia.) are ecore with just a couple/few exceptions.
The Fram Xref show the PH 500 to < 3", so perhaps not an ecore.
You could likely confirm by checking the equivalent make/model application ST at Wally or STP at AZ, that would give you a good indication without going to Firestone.