In the pre-Go-Go era, lunch at the Bankers Club was a genteel affair with a sea of Brooks Brothers gray unbroken except for the subdued accents of the rep ties. Since then, the double-knits have arrived--sharp, aggressive and all teeth. Like Martin T. Sosnoff, erstwhile Forbes columnist, who will tell you in his racy, snappy patter how he started at the bottom selling cat balloons outside Macy's and later got hauled in during the Princeton-Dartmouth game for peddling chrysanthemums outside the stadium. Revenge is sweet, and at least half of what Making It is all about. Then there's money. . . . And then there's the hearty enjoyment Sosnoff takes in out-thinking the other guy. This is not exactly a pitch. In fact, Sosnoff can hardly follow a straight line from anecdote to anecdote. Mostly these are case studies in the long positions he's taken during the five years the market has been sinking into the mud. His investment philosophy is ""garbage in & garbage out"" in the short term. Nevertheless he gets burned so often that by the end of his ragamuffin-to-money manager tale, he's wheeling and dealing in options--and selling them short at that. Better he should go back to cat balloons.