The "Golden Era" is from about 1900 to World War II. Many would say from the end of World War I to the beginning of World War II. The latter gets my vote because of the huge variety of models and the amazing quality, but leaving out the Colts with the high polish from the Pre-World War I era is a tough call. The "Golden Era" is not just confined to Colts. The Winchester, Smith & Wesson, Savage, Marlin, Remington, etc. lines also exhibit the same quality and variety that did not survive World war II.
I am surprised to see anyone claim that period encompasses the 1970s! I must assume thy have not examined any Pre-War guns. There is no comparison.