Update, used my first part from my parts car, the cassette module. After checking that it didn't have a cassette stuck in it, too, I pulled the unit from the dashes of both cars, removed the cassette modules from the dash stereo units, and swapped them. I even discovered where the missing screw belonged. Even more surprising, I hadn't lost it between last week's foray and this weekend. Now I happily have the radio back, so i can use my hands-free phone Bluetooth FM adapter. Whew, what an ordeal.