usually not for the HS. There is usually a void between the daughter card to assist with radiant heat. The HS usually has a portion that makes contact with the CPU and it is specifically lined up with the location of the CPU.
As for volume and eject, I believe one of the Function buttons will still eject (F16 i think?) Keep in mind the volume can be controlled by the title bar. It's a shame you are not close to me, I would just give you a slot loading G3 keyboard with volume and eject buttons.
Eject usually is F12.