Trekkie, did you check the link I posted?
As far as MC meeting the requirements of 517-13 (99 NEC reference) some types can meet this requirement and the smooth type is one of these, but this still is not a "Hospital Grade" cable.
Yes, I have seen the smooth type MC, and you have too most likely. Some appliances have it installed from the factory, but as Iwire says it is not common in our field.
And I will say again, Hospital Grade MC does not exist, HCFC is an AC hybrid.