I'm replacing the control on my furnace. The new control has two extra terminals marked 24V and 24V GND . I looked at the Transformer(load side) which has a black wire under the screw marked 12VA and the white wire under the screw marked 24 Volt. Are either of these wires 24V GND?

Usually ground is not part of the circuit and the Line and Load are isolated from ground, Ground is usually good when it is bolted to the metal chassis.
12 VA seems light, Was the old one 40 VA or other?