There are two definitions of pistols according to the rcmp. Ones with receivers initially designed as pistol receivers, which get you pistol mags, and pistols converted from rifles which still just get you rifle mags. IE a rifle modified into a handgun.
The ar15 and xcr have receiver versions that are constructed as pistol receivers as birth and are stamped as such.
The vz58, according to the rcmp, does not.
That is why we have ar pistol mags, and not vz pistol mags, according to the rcmp lab.
The vz skorpion will likely fall in that same boat. Additionally there is the oic that says skorpion pistols are prohibited. Pretty generic, but that may limit us to the rifle versions as the rifles were made first, and aren't a variant of the pistol version. Just like the vz61.