pjbizjak, the 4053 carburetor wasn't used in any 1973-1975 General Motors "production" engine, and was only used during the 1968 and 1969 Model year, therefore, this carburetor is an "over the counter service replacement". An original "production" 4053 carburetor (for 1968 and 1969) would have a 3 digit date code. As this one has a 4 digit date code, it indicates the carburetor was manufactured after 1973, a full 4 years after the 1969 Camaro ceased production.
Perhaps you're confusing the terms "aftermarket" carburetors (which this isn't), with Chevrolet "over the counter service replacements"?
Ed