I did a hell of a lot of it back in the late 70's/early 80s. Actually it was usually multiple toning, sometimes multiple chromogenic re-development with different colour couplers and only then a bit of hand colouring to finish off.
Unfortunately much of the work was one off, and I have no copies, quite a few were album covers but I agreed to remain anonymous.
Bob Carlos Clarke was the ultimate master of hand colouring, we swapped technique sometime around 1985.