Little did I realize until today, though, that they were taken at Trude Heller's! A crucial bit of background proof was cropped out of the above photos, but it does appear in the images which illustrate the fantastic interview with Patti Quatro in the current issue of Ugly Things (#31).
I also just found this photo here, with the telltale Trude profile logo behind them.
Looks like the Quatro sisters are in the process of developing a site about their musical history, quatrorock.com. In the meantime, get your grubby mitts on the new UT, which as usual provides hours of indispensible rock and roll reading...other particular highlights for me include the to-die-for Norton Records Silver Anniversary Story and an interview with Prince Stash Klossowski de Rola.