Are all the items marked "second"aluminum? The 2 I have the following,Wagner Ware Sidney-O-NATIONAL ALUMINUM SKILLET,PAT, APL'D FOR 10" I. The other is,Wagner Ware Sidney -O-,507 C I also picked up a hammered Wagner Ware skillet with what looks like 3503 but is not marked "second". Anyone able to tell me if that is the correct number? It is 7" pour spout to pour spout . Thanks for any info. Tom