You have it reversed, sir. The 71 was the air metered. The rest were solid fuel metered. I am not familiar with how the comp models were metered though.
The 'Competition Series' and 1971 Thermoquad Carburetors use the 'conventional'
Air-Bleed Metering System.
Air is introduced into the Fuel Stream {before} the Fuel discharges from the Nozzles.
1972 and later Thermoquads > are 'Solid Fuel Metered', which means that the Fuel
Metering System feeds the Primary and Secondary discharge nozzles with a continuous
stream of fuel that mixes with the Air {after} it leaves the nozzle.