Only switch to weapons already in inventory

Good evening everyone,

I have a weapon switching script that works just fine, but now it's time to take the next step with it, namely, I don't want the player to start out with any weapons; they need to buy or find them. So I've modified my inventory script to be a weapons inventory, and tried to call it from the weapon switch script, so far, with no success. I think the idea is right, I just haven't implemented it properly, and am hoping that someone might be able to steer me in the right direction. Thanks, and God bless.

 function Start () {
     // Select the first weapon
     SelectWeapon(0);
 }
 
 function Update () 
 {
     if (Input.GetKeyDown("1"))
     {
     if (WeaponInv.inventoryArray[0] > 0)
     {
         SelectWeapon(0);
     }    
     else if (Input.GetKeyDown("2")) {
     SelectWeapon(1);
     }
     else if (Input.GetKeyDown("0")) {
     SelectWeapon(2);
     }
     }
     }
     
     
 
 function SelectWeapon (index : int) {
     for (var i=0;i<transform.childCount;i++)    {
         // Activate the selected weapon
         if (i == index)
             transform.GetChild(i).gameObject.SetActiveRecursively(true);
         // Deactivate all other weapons
         else
             transform.GetChild(i).gameObject.SetActiveRecursively(false);
     }
 }

(Note: only the first weapon is attached to the Inventory right now, as I'm just trying proof of concept at the moment.)