No point to it. Although they seemed to become standard in the
late 70's on almost anything. No point on one
with a hot bridge either as chassis is always hot. Probably laws.
On the service end if it came polarized it went out polarized.
What happened at home to it stayed at home.
BTW one of my favorite pass times is filing plugs, ripping off
safety tags and of course furniture tags. See feb 1972 cover here.
http://lampoon.rwinters.com/Lampoon1972.htm
73 Zeno
LFOD !