Here's some comparisons of some different 121s. When I have access to my main collection again, I'll be able to post some photos of other 121s, including denver molds and the pleated skirt 121s.
California CD 121. The California CD 121s have a unique wire groove and wire ridges. The bottom WR flares out a bit, kinda reminds me of an early lilly shell multipart.
NE Duquesne 121 - This is a round dome variety, and features four ribs under the very square lower wire ridge. This has a very round dome.
Gayner CD 121 - This is the same mold as the Lynchburg CD 121s. These have a flared skirt and small, round dome.
NE AGEE 121 - This shows the shape of Australian CD 121s, with very rounded wire ridges and grooves. The sides and crown are very straight, with the dome being quite flat on top.