IIRC that 1.88/1.50 valve size for the '67 920 heads is a misprint that has propagated throughout the internet. I've seen it so may times yet I cannot find a part number for a 1.88 intake in 1967.
Never happened. All Original Commando/Charger heads were the standard casting with the same 1.78 intakes and 1.50 exhaust valves as the 2 barrel engine. Only the valve springs were different.