Those condition codes are pretty specific to a sa firearm with a hammer, one of Mr. Cooper's favorite firearms being the 1911, this makes sense
the military also utilizes condition codes for firearms, and there are only 4, 4 to 1. However due to the difference between one firearm and another the condition codes can change up little bit by bit.
M9 Condition Codes:
4: Chamber empty, slide forward, no magazine inserted, safety on.
3: Chamber empty, slide forward, magazine inserted, safety on.
2: Does not apply.
1: Round in chamber, slide forward, magazine inserted, safety on.
You see that there's nothing about a hammer in these codes, and the safety is ALWAYS on until ready to fire (as per universal firearm safety rule 4) and taking it off and carrying it as such is not a carry code.
Out of uniform I carry firearms with no manual safeties. I still refer to them as Condition one, despite the lack of safety. Condition Zero has always sounded dumb to me, to my mind condition zero sound more like out of ammo or dead, IMHO.