Problem, in MY mind with turning the AC plug 180 degrees to eliminate noise is that it can put the switch, fuse or circuit breaker on the "wrong" side of the line
I determine which orientation gives me the lowest voltage on the chassis (and subsequently the lowest noise) and move things as needed to maintain modern orientation to the mains (keeping the 120 switched) and keeping all circuit protection devices on the "HOT" side, between the load and the switch
With the use of modern X1/Y2 safety caps on the line, this should be fine theoretically in and of itself, assuming the outlet is wired correctly, your breaker box is right etc
I also included a 3 wire cord on my first and only complete rebuild so far as it lowered the noise factor and chassis voltage even more
Not to mention the additional factor of being even "safer"
Marshall