There is no way McCoy would treat him as anything but a pretty toaster.
I haven't watched TOS as much as the other series, but didn't Bones say once that he'd rather resign than be replaced? I'm sure he would hate the idea of a piece of technology taking the place of a flesh-and-blood doctor. He'd probably treat the Doc even worse than Zimmerman did in "Life Line".
On another note, I just found this on Memory Alpha:
Holographic Doctors, under development in the 24th century, included McCoy in their templates.
Well. There you go. It's not corroborated by any references to episodes, but I suppose if you accept Memory Alpha as a credible source, then that answers that question.