It's unfortunate that the book doesn't provide more guidance on this, so "Ask your GM" (or "Make a GM call", as the case may be) is the only good answer. You just have decide how broad each license is. I personally take each individual table as a single license - after all, there are non-weapon restricted items, and it makes zero sense that a single license would cover them all, but likewise the difference between two similar items in the same category it makes very little sense that a single license wouldn't cover them both.
So I break it down into "Heavy Pistols license", "Explosives license", "Electronic Warfare license", etc. I consider the "Concealed Carry license" to cover the Firearm Accessories table, since it includes things like the hidden arm slide, although that one is kind of iffy. Just makes it easier and faster.
It is important to note that the licenses only matter if you get caught with the items - assuming you have them running silent (or have the wireless turned off), it may never matter. If you have a license, though, you don't need to leave them on silent running, and just look like a smart citizen carrying legal protection to a quick look. (Of course, heavily modified or very restricted items could provoke a harder look, that might test the integrity of your fake license - and SIN.)
TL;DR: I use a license for each category of item that can be Restricted, such as one for Heavy Pistols and another for Machine Pistols and another for Explosives. This most closely matches most real-world licensing laws (having a permit to use mining explosives doesn't allow you to carry an Uzi, but having a permit for a 9mm Colt does allow you to carry a .22-pistol S&W), seems to make the most sense, and simplifies play without making the notion of licensing (and fake licenses) obsolete.