96 Buick Park Avenue upper manifold removal procedure

Do you have to drain the coolant out of the radiator to just replace the upper intake manifold on a 96 Buick 3800 vin k? The service manual procedure says no but other sources on the internet say yes do drain the coolant. Is there coolant flowing through the upper intake manifold or not?

Yes, drain it. Should do lower gaskets, use the better updated ones from Fel
pro. while it is apart.