[Yashas]

Код:

public OnPlayerUpdate(playerid)
{
         if(GetPlayerWeapon(playerid) != WeaponIDFromInventory[playerid])
         {
               SetPlayerArmedWeapon(playerid, WeaponIDFromInventory[playerid]);
         }
}

I gave you an idea, it is up to you to modify it and make it work with your script properly.