Calling GetPrimaryWeapon() (or GetSecondaryWeapon()) will suggest that a returned weapon is active atm in either of the two weapon groups, if it's active in at least one group.
F.e. assume the following weapon setup of your ship with a single weapon:
- weapon is active in group 1 and group 5
- currently you have group 1 and 6 active
In this case, calling GetSecondaryWeapon(1) will (incorrectly) suggest that the weapon is active, while it's only active as a primary weapon group weapon.