I don't know if anyone here is interested, but I was at the Ollie's Bargain Barn in Myrtle Beach S.C. and found in their surprisingly extensive Gun Books Section a copy [they had plenty]of "WINCHESTER SHOTGUNS" by Dennis Adler the coffee table book for $9.95. It has a section on Model 21's and Parker Reproductions that has some great photos of most of the variations of these 2 models. If you have an Ollie's nearby it might be worth a look.

H

It has very nice color pictures of Winchester shotguns and well worth price for that reason. Our Winchester expert Ole' Cowboy of Texas now sadly gone said it had number of inconsistencies in print. I would not know because I'm not Winchester firearm expert, apparently one must be cautious about what they read in there.

Jägermeister, I think what ever book you find on any shotgun there is always going to be inconsistencies, especially when written by one person. No matter now well their research was there is always something new to show up.
I look at it as if I didn't know, it's good enough.