That's the kind of thing that gets kind of iffy for me. Because that's very setting dependent and, theoretically, the Central Supply Catalogue is core rules. By default, Traveller has laser, sandcaster, and non nuclear missiles in turrets as what is legal for civilians. But the implications of the comments around the PD Lasers in that sector book is that the smaller states out there are much more restrictive, because their militaries are less able to laugh of full lasers and missiles.
And what needs to be on the black market is going to be different from world to world. So I would rather it be a coherent set of rules for how to set up and run black markets, with an "example" rather than anything that smacks of "rules" about what things are what legality.
But the the whole "properly separate Traveller Core Rules from Charted Space" is my particular windmill to tilt at. heh.