Yes, they do. I have the identical model shown in Snake's photo for my flintlocks, and another one designed for caplocks. I bought both of them decades ago when coaching 4-H.
I will add this thought though - I always used this method first. If other methods have already been tried in removing whatever object is stuck in the barrel - it might be too late.
For example:
If a hole has been made all the way through a patched ball when a screw type puller was attempted, I doubt the Co2 tool will work. If a ball was short-started with two patches (student was busy visiting while loading) and instead of using the discharger immediately the shooter decides to beat the charge all the way home with a roofing hammer (yes, he really did) no way was the discharger able to overcome such a wedged cylinder of lead.
There are other scenarios but you get the idea.
At one point I felt the need to slug the barrel of a .54 caliber rifle. Found a lead conical laying around the shop of an appropriate diameter. Pushed it all the way home with no patch or powder - just some lube. Placed a 5 qt. ice cream pail on the floor with a hand towel in the bottom, had the muzzle of the rifle an inch or so above the towel and used the Co2 discharger. Bullet ricocheted off the towel, one wall, the ceiling and a second wall before coming to rest.