Well, Glenn did open for Fleetwood Mac in 1982, and back around 1976 when Stevie was "on intimate terms" with Don, he was still living with Glenn. Remember that story Stevie tells about Glenn teasing her when she was having dinner with Don at their house - "spoiled yet?" Glenn asked her, much to her displeasure, lol.
For a couple quotes from Stevie on Glenn, see the old Glenn and Stevie thread from the Flip City days.