it is very difficult to see the signature, but if that is supposed to be a 1979 version of Munson's signature, it is way off. It looks more like a late 60's, early 70's attempt.
+1. It's closer in style (though still off, as Terrier stated) to his 1969 style of signature than his 1979 signature. Being that 1979 Munson team ball signatures are rare, Munson not signing liberally at this point in his career, if real, the price should be many, many multiples of $125.