A little looking turned up this which expands a bit on the 0-level Apprentice rules in 3E.
I seem to recall 1st Edition had some rules for commoners, but it’s been a while so I might be wrong.
@majorrich Looking at the stats of a common housecat, a ½ HD monster, I would go with 1d4 for commoners myself. And I’d like to think that that drunken blacksmith has more hit points than the glass mug he’s drinking out of.