Thanks for the question.
Identifying other parts, like the barrel figure and the slide, would make it more difficult for anybody to order parts and make them. Then if they're caught making them, they will be caught making a weapon and they can have bigger jail sentences.
It would be easier for the authorities to arrest somebody who is importing those parts in Canada. At the moment, they are part of a weapon, but they are not identified as a weapon if a person made the parts themselves. That's the first thing. The other thing is that the government should be thinking about asking firearms producers to give identification numbers to those parts.
Also, the Canadian government should think about how to forbid anyone from creating or importing 3-D printing machines that are specially designed to make weapons like the Ghost Gunner, made in Texas by Defense Distributed. This is one of the best known examples, but there are other such devices or machines that are available online. That being said, regular 3-D printing machines should stay available.