I believe the Dragon's Tooth always did 100 damage; the difference in the early patches was that it did 100 damage in a single hit instead of 5 simultaneous smaller hits.
It seems you are right. Well then, I just have to rationalise that JC is not a sword-guy and stick with the combat knife. Over the years my tens of playthroughs have always been more or less minimalist stealth with only the dragon's tooth for a few kills. I'm really trying to break the habit this time. I'm not sure if I ever did a sniper playthrough and I certainly have not gone assault rifle or shotgun.