Thanks for clearing that up, derf - I was curious about that.
Just replaced the rear speakers in Mrs. Panic's last week. I ordered the cheapest pair of 6.5" that Crutchfield had and used their mounting brackets and wiring harness adapters.
Here's the bracket and wiring harness installed:
The supplied hardware could be better for the brackets, the screws are ridiculously long for this application. But the holes all lined up without incident for the bracket. The tab for the bottom screw comes down fairly far and I think it might slightly be in the way of the bottom edge of the door panel but doesn't seem to have any adverse effects.
I did have to buy shorter screws for mounting the speaker to the bracket, the ones that came with the speakers were far too long. Added double-sided tape to a few places on the back of the brackets to (hopefully) eliminate some rattling.
Good luck!