I know that when I picked that 20" skillet up I asked for information here to figure out if was a Griswold... I seem to recall that there was a marked Griswold, a unmarked Griswold, a Wagner made with the Gris pattern (almost the same), and I likely missed something...
I'm speaking only of the Griswold/Wagner 20 inch "family" here, then there's Lodge and BSR...
Glad I got it to a good home, my limit these days is a #14 ;)