If you are going for correctness, the air cleaners in all the catalogs are not correct for cowel induction or other 1972 Chevelles!!
They do not have the correct thermac valve built into the snorkle part of the air cleaner. If you are trying for correctness purchase yourself a Chevelle restoration guide like Motorbooks International "Chevelle SS Restoration Guide by Paul Herd, or some other noted restoration guru.