Yes, those are the speaker terminals. They puzzled me for a while too until I found a copy of the service info. The handful of rotted wiring I thought was for the speaker I showed in an earlier photo was actually an antenna.
Speaking of speakers. I got lucky and found a nice Brunswick Model A on ebay
As far as I know, it's the speaker that originally went with the 5KR.
Coincidentally, this speaker was missing the plug pins. I was able to salvage them from 5KR chassis and attach new wires.
It has a handy access port on the back. A little tug in the finger holes on the bottom and it pops right off.
I hooked it up to a function generator and it seems to work very well
The cone is in excellent condition.
