I drop by various thrift stores a few times a week, Sunday I looked back into the electronics section of the local goodwill and I could could see the POLK badge from 50 feet away. I got just a little excited, this was the same place I'd found a pair of M5JR+'s for $15.
I got close and saw a pair of black bookshelf speakers, but when I pulled the grill they were naked carcasses, no drivers whatsoever: I was very sad. They had mounting brackets but no markings other than the grill badges. Since the wire connectors were still attached and the crossovers were still intact, I pulled one and got the part number from the PCB and was able to identify them as RT5's.
The cabinets and grills were in great shape, but the with the drivers missing they seemed a lost cause so I walked away.
Whoever pulled the drivers even left the screws in the cabinet...