Yay! Thanks Lee (Sparky)!
I guess my unit really needs a cleaning! After removing the brass clip, I had tried to push that shaft back toward the gear side and it didn't want to budge at all, so I figured that since my unit looked different than the one in the Tech Tip, it must come apart in a different fashion. But, after looking at your post, I went back out to the garage and with a bit more conviction than I had before, I convinced that shaft to slide toward the gear end!
I am definitely getting further into this speedometer than I had intended, but if it works when I am done, it will look so much better that it will be a victory.
I have ordered a decal set that includes the odometer wheel numbers, but, being lazy and a bit intimidated by the prospect of taking the odometer apart, I had hoped that I wouldn't need them.
Thanks for getting me un-stumped!