Uh, kind of? It has been shown that there was some contact between the Polynesians and the west coast of South America. The Kon-Tiki hypothesis is usually understood to be something like "the Polynesian islands were populated by a group of indigenous South Americans who drifted there in a boat", which is certainly not exclusively the case (an overall west-to-east migration to populate Polynesia is all but certain and corroborated by evidence across multiple scientific disciplines) and might still not even be partially the case, as the contact could have been Polynesians sailing to South America and back (as the paper's authors acknowledge).

Given that we know the Polynesians to have been expert navigators who explored basically the whole Pacific basin over the course of centuries, that explanation for the contact seems more plausible to me than the drifting-from-South-America explanation for the genetic admixtures reported last year; but even if you think otherwise, the hypothesis wasn't really "proven right".