When Mannix is standing outside of Wing Dobson's studio, there is no reflection in the window, so there's no glass in the window.
While working out, the rock star appears not to know what he's doing with dumbbells and weight machines. He does a zig zag pattern with the dumbbells, which work out no muscles in particular, then rapidly and haphazardly lifts the bar on the weight machine, badly and barely exercising any muscles at all.