I am making a pickup weapon script and I want to check if a weapon slot already has a weapon stored in it. If there is a weapon in it then I want the weapon to be stored in the next weapon slot.
If weapon1 is your gameObject container you can use
if ( playerWeaponManager.weapon1 != null ) {}
to check if its full.
But then it seems you already have a bool which you can use to handle it?
playerWeaponManager.weapon1Attained = true;