Rocket, just my casual observations from viewing Gunbroker and Auction Arms, and trying to compare the American guns using your system, I would say without a doubt that Parker carries the highest Brand Value BV of the American shotguns. Next in line comes the Fox, a recent surge over the last few years, past the LC Smith but that margin in BV is growing steadily. Winchester M21 next but by a slim margin and then we have LC Smith over Lefever's 'automatic hammerless' by the slimmest of margins and next but farther down on the list, a wider margin, the Ithaca.
So to be a bit more graphic
Parker

Fox
Winchester

LC Smith
Lefever Automatic Hammerless




Ithaca

In my humble opinion this is the way I see it, BV1 is Parker; BV2 Fox and Winchester; BV3 LC Smith and Lefever; and BV4 Ithaca