Thanks for your help folks, but I figured this one out this morning.
Apparently the Rider schematic I ordered was for a Silvertone model 4585. I was sent the diagram for model 4585, chassis no. 100.151. (4585 is the number printed on the chassis sticker.)
I checked
http://www.nostalgiaair.org/Resources (which seems to have a very good list of .pdf schematics) and found the rest of the story.
Included within that Rider volume was a schematic for the chassis no. 101410, which matches my radio.
I'm not sure if Sears was the only manufacturer that did this, but I've never seen different chassis numbers within the same model number. Now I can do some serious damage.