Thanks for the add'l info Len. It is very likely you are right about the audible buzzer being lost in the conversion to negative ground (long before my purchase). I checked around the rear door area and there is no sign of any switch left in that area. I have a new switch to install and have already run new wiring to the dash area.
Selenium rectifiers? Is that right next to the flux capacitor?
I think I'll dump the selenium rectifiers and replace them with dilithium crystals. That outta get my Detroit Warp Drive unit rocking.