I went ahead and bought one, it wasn't very expensive, I'll see if I can install it...if not, I'll keep that in mind. Hardly any other old cars even have such a part, so I know it's not totally necessary, although if it's not there, the rear brakes could be more likely to lock up when you really don't want them to.
I got the clutch working again, and went for a longer drive...made it all the way to the parts store this time, which is a significant milestone
Tinkering with lights now, the right rear stoplight was not working, could not get it to work, replaced the entire light housing with one off a parts car, now the tail light on that side refuses to work...I'll pull the light assembly off the other parts car, and try it, and if that doesn't work, I'll start drilling out rivets and replace individual socket(s).
There isn't enough room for my big foot to fit between the brake pedal and the transmission tunnel. Pretty annoying.
The temp gauge is not reading very high now, the engine seems to be up around 160-180 after a drive, so I think the thermostat is not stuck open? I'll have to do more investigating why the gauge only shows a little over 100 degrees.