Yeah - they would
This actually scares me - now you have to be REAL careful buying/selling 10/22s
If you have a rifle with a reciever that was originally a pistol, or the other way around, you have illegal NFA weapons - the BATF can cause you all sorts of problems
Just want to clarify, you're half right.
According to the BATFE and case law, a firearm that is originally a pistol CAN be reconfigured into a rifle (16" barrel, 26" overall) and later returned to pistol configuration. That is completely legal. However, a firearm that is originally a rifle may NOT be configured with a barrel less than 16" or an overall length less than 26" (without going through the NFA registration process beforehand).
So if you have a 10/22 rifle, you cannot make a pistol out of it, ever, legally. Even going through the NFA registration process, it would still be a short-rifle/short-barreled rifle (SBR) rather than a pistol, regardless of the presence or lack of a buttstock.
But if you buy one of these 10/22 factory pistols, you can add a 16" or longer barrel and a buttstock (must be in that order to prevent SBR status; reverse order when changing back) and also have yourself a 10/22 rifle. This is the law thanks to Thompson/Center Arms winning against the BATFE for going after their Contender pistols sold with rifle kits.