It's hard to see how you could violate this proposed law since it includes grandfathering of existing weapons. The way I read it, it would apply only prospectively.
The country (including Colorado) is awash with these types of weapons. Anybody who hasn't already stocked up has been asleep at the switch. Therefore, the actual effect of such legislation (in preventing mass shootings) will be minimal. The sponsors surely know this, and this legislation is an empty gesture.
The next step would be confiscation of existing weapons, but that's where they would really run into non-compliance. Notice, however, that this legislation doesn't include a registration provision, which would be necessary for the next step. It seems to me that the legislators are unwilling to go there.