Wht Miriam said, I think it's safe to assume it's right. Singer are mostly left, but they did make some that are right for some years, but I forget what period of time it was.
BTW - these are also called 11 o'clock and 1 o'clock - indicating where the finger points to if it were on a clock.
All of the non-singers I've encountered so far have been 1 o'clock fingers.