Don't feel too bad. I had an exchange with the RCMP some years back about the legal status of the Model 1 in Canada. Low and behold, it's a Prohibited Weapon since it has a barrel of less than 4.1 inches and it can chamber "modern" rimfire ammunition.
(It's true that one could load a .22 CB cap, or even a .22 Short in a Model 1, but the gun was designed for a .22 black powder round and there's a chance of splitting the cylinder with modern ammunition.)
So long before the 15-22 became an evil gun, the Civil War-era Model 1 was already on the poop list.
Mike