Can you specify the location that you need the screw?
The second link you shared can not be opened.
Not a good news for you.
The screw, together with the cooling chamber is a special module designed only for this QY model.
The screw can not be completely separated from the chamber cover or they might breaking one another.
We don't suggest to replace the screw by yourself. We are replacing the whole module all together when repairing in the service center.
So you can consider as this screw is customized product and can not be found on retail market.
Who told you that....
The QY model is having different spec than other G513Q model.
It is true that other G513Q model have the screws that can be bought on the market.
Just double confirm that "ASUS engineer" that you are really getting the right spec for your QY model.
And if you are lucky enough to detach the screw yourself, then good luck! Go ahead if you want.
We do not sell that cooling chamber.