you are comparing a part number to an engineering number. the COAZ-A part may have the C8AE engineering number depending on the supercession of the numbers by ford from 1960(COAZ) to 1968(C8AE ).
parts do not have a part number on them it is an engineering number there is a translation catalog to get a part number from a engineering number. i would not sweat this at all use the part. the oiling mods you do to the block at the
oil filter location will give you more, than worrying about a few thousanths of an inch of material in the housing.