i realized you are correct yesterday while installing one for a customer. the bluetooth adaptor comes pre-installed in the rear usb cable and is about the size of your thumb nail, which is why i didn't snap as to what it was. lately we have also been getting a second ks-ubt1 in the box along with the one already in the rear usb. thanks for pointing that out
i was just reading your info about the JVC KD-A805 (not kda-805), the bluetooth is done via internal adapter, so there is no external usb connection. the only thing you plug in is a mic cable to a mic jack attacted to the back of the radio. this might be confusing to customers if they self install and cannot locate the usb adaptor
thought this might help a little