It is standard practice to have fake licenses for your various gear. These licenses are tied to your fake SIN and their rating cannot exceed that of your fake SIN.
Occasionally you may want a real license for gear. In order to have a real license, you must take the SINner negative quality. Once you have the SINner quality you can purchase licenses for restricted gear for 250 nuyen. (price subject to change)
Be aware the if you are caught in criminal activies while using your legitimate license they will know EVERYTHING about who you are. Depending on who learns this information your life could become much more "interesting".
Licenses are obtain for a specific "type" of item. In the case of weapons, this will roughly map with the associated skills. IE – You can have a pistols license, a longarms licence, a blades license, etc.
If you have redundant licenses purchased before this ruling, you are entitled to a full refund.