Need help with a Borderlands style proficiency system.

Well for any of you that have played Borderlands, you will know tat there are two forms of leveling in it. One is the main level, and two is the weapon proficiency levels. I am trying to develop a similar system. Although I am unsure of how to go about it. I know what I need to do (one way of doing at at least). It is like this, I would like to make a script and attach it to each weapon and maybe give it boolean values like this :

 var isAssaultRifle : boolean = true;
 var isShotgun : boolean = false;
 var isPistol : boolean = false;
 var isSniperRifle : boolean = false;

So as you can see this particular weapon would be an assault rifle. So now I need to make sure the player knows its an assault rifle and ONLY returns the damage it deals to the assault rifle proficiency. For example, when I switch weapons I obviously don't want to be shooting with a pistol and having it return damage to the shotgun proficiency. So any ideas would be greatly helpful, and I appreciate it ahead of time. Thank you! :)