"Old"? You are aware that was a brand new state of the art system at that time, right? Oh, and it was not in Vietnam, the Soviets at that time were not exporting that system.
However, once again you simply prove you do not actually know what you are talking about, and simply making crap up in the hopes that somebody will believe your coprolite without checking it. Because the system used in Vietnam was not the S-200, but the SA-2. And it was a highly capable system, being the same one that shot down a U-2 in 1960.
You know, you really need to stop simply making things up. Because that really reinforces the fact that you do not have a clue about what you are talking about.