Yes, that will work. I was going to pop in here and mention it myself, but FM beat me to it. As far as I can remember, even a SEALED weapon or tool would seal that limb.
I see a problem with this, though- harnesses are indestructible; only their contents may be damaged. This means that wearing a SEALED harness gives the player permanent vacuum protection. Maybe I should give harnesses a damage rating, although I seem to remember that there was some reason why I didn't want to.