More progress today... So I had heard about how cheaply made the Bose drivers were, and after seeing them for myself, yeah, they are pretty cheap. Plastic baskets (not always bad, but not impressed with these), really thin paper cone, very thin rubber surround, small voice coil, puny magnets.... I am happy to see them go.
They are good for one thing however, The basket can be gutted, and used to mount the Tang Bands, or I imagine most any other 6.5" speaker. With only a pair of wire cutters (a.k.a. dikes) one can remove most of the basket, the cone, and magnet assembly, leaving only the circular portion of the basket that bolts to the door panel. Epoxy the basket to the back of the new speaker's mounting flange, and viola, you have a nice, clean mount for your new speakers. In the case of the Tang Bands, they needed to be spaced away from the door since they have a much greater mounting depth than the Bose drivers.
Here is the Bose basket after removal of the cone, surround, magnet, spider, wire leads, and connector. It has been placed onto the back of the Tang Band's mounting flange.https://photos.app.goo.gl/ojsV9H1d2MDpDGGx2
Here is a close up of the epoxy used to glue the Bose basket to the Tang Band's mounting flange. I taped the Tang Band screw holes to hold in the epoxy, roughed both surfaces with 200 grit sandpaper, pre-coated both mating surfaces with epoxy, assembled them, then ran another bead around the outside perimeter of the joint. The plate is used to support the Tang Band by the flange. I suppose you could set it down on its surround, but I do not recommend that. https://photos.app.goo.gl/7Ep42JiU4zUoc94g1