The lies they do identify were either (i) made when he was in high school (and if that is it, then ok, let's go with that), or (ii) cryptic terms which are interpreted to mean "X" today by people who oppose Kavanaugh, when the people who spoke the terms 36 years ago claim they meant "Y" and still claim they meant "Y." "We know today what they meant 36 years ago by that made up term." It just seems a stretch to say that is sufficient evidence of perjury.
I admit as well that I haven't followed the Saga of Kavanaugh's Lies closely. But, I'm not the one making claims about it. I honestly expected those who do make those claims to come up with some clear examples of lies. But, their best argument seems to be, "Oh, c'mon, of course he lied, let's go scratch on the doors of SCOTUS like cats."