I personally have not tested it, but scrolling through all the comments on it reveals most people saying it does not. This is due to the fact that the dart is based off of a regular tranq dart, so if a creature is immune to that, it won't work either. Which means cannons are still the only thing able to do it.
This is all stuff I found said in the comments. Like I said earlier, I didn't test this, and due to the fact all of my singleplayer maps are running their own mods, I didn't want to mess with that. And I checked the change logs, and didn't find anything saying that it is now able to KO rock golems. Sorry that I couldn't give you a definitive answer!
And yes, I do realize this is more than a year late, but it still has gone unanswered, so I figured I'd do it.