Biologists predict 5% rooster survival is all that is needed for full reproduction numbers. Even hunting pressure in SD takes only about 45-55% of roosters. If almost every SD hunter doubled their current success rate there would likely be little effect on numbers the next year. I think bag limits are a poor management tactic in many conservation scenarios. More about GFP/DNR flexing and making a reason for them to exist.
Would you even take the extra bird at this point if they allowed it? I barely get through the 15 I take home every year and that's breasting them out for most of them.