Canon did not begin labeling their lenses with the S.C. and S.S.C. designations until March 1973 when the second generation of the FD breech lock lenses began appearing. None of the FL lenses and none of the first generation FD lenses (sometimes referred to as the "chromed-nose" lenses) carried the coating designations. Most of the first generation FD lenses had S.C. coating, but a few had the S.S.C. multicoating from the start. As David noted, Canon deleted the S.C. and S.S.C. markings on the New FD lenses which have the breech-bayonet style mount. While it's true that the FD 50mm f/1.8 lens never received the full S.S.C. treatment, some of the elements in the S.C. and breech-bayonet versions are multicoated. Flare was very well controlled on this lens so it didn't need multicoating on every lens element.
My understanding is that nearly all high quality lenses manufactured after WWII have coated lenses.
I can verify this my chrome nosed FD breech lock 35mm f2 Thorium lens which was made in November 1971 isn't marked with SC or SSC.