Well, if it is a cut-down arty barrel, the front sight base/band will be silver-soldered on...Can you see a circular line on the muzzle??? A lighter colored line around the rear of the band???
And if it's a cut-down arty, they turned the rear sight base off on a lathe and tapered that section...which would leave a flat on the top of the barrel flange, where the rear sight sat...
And they would have had to re-blue it...
The silver-soldered front sight band (or lack) would be the definitive proof...
Edit: The flange itself looks too thin for an arty...