Exactly, that era or time frame would be more reserved for planes that are 3rd generation. Planes like the F-14, F-15 and Su-27 as we know are too OP for a Cold war type of scenario, mostly because of their awesome tech and excellent flight dynamics. It takes away from the cold war authenticity.
It's like adding the F-80 and/or F-86 to a WW2 server because they were so close in timeframe. Ok maybe the Sabre was a bit too far and came much later but the shooting star (even though we don't have it). But you get my point.