It appears to me that the post-1925 Model 30 numbering sequence (for all makes, including the Riverside versions) is Model 30 for the plain barrel field-grade guns, Model 31 for solid-rib versions and Model 35 for the post-1938 non-suicide safety guns. Sadly, I have only seen photographic examples of the Model 522s (the Trap Model) and the 535s. Beginning at the field-grade, plain barrel 520 for $25 and ending at the Model 535 for $100 (w/522, 525, & 530 in between). The model numbers and prices are interesting. I also carefully looked over the early 520 advertisements that Dr. Both of the Western Field Model 30s I own have the later (#74) type of ejector, but the 12-gauge doesn't have the front breech-block screw on the left-side of the receiver (the 20 does). Jim: Went back and carefully re-read your original post (with all the additional photography).
