I just checked my TM501 (Not TM501A) modules, all four of them in my collection have Q12 on the left, Q10 on the right.
I also just plugged my tester module in to each and the +15 and -15 LED's lit ok when the rotary switch is set to Position 3 (+15V should be out when in Position 1, -15V should be out when in Position 4)
Jared Cabot