Some of which, I'm given to understand, are LCAFD, not that I can find that written out in the currently published Code.
Which seems to rely on firearms being immutable, unchanging things.
So, a 5 round 870 mag extension tube, appears to be a benign LCAFD. Unless it's assembled on an 870, where it may be an AW accessory, but only after assembly.
The poor crafting of this law is both boon and bane. It's obvious failings may make it easier to overturn, once the wheels of the courts finally advance. It's a bane, as "we" do not need the "antis" to be any smarter about how to craft these despicable ordinances.