Well, there have been the Resident Commissioners from PR...
Other than the Resident Commissioners from PR, Labrador would indeed be the first Republican Congressman of Puerto Rican descent. If I’m not mistaken, the closest a Republican of PR descent has come to being electedcas a U.S. Representative was Joe Negron in tbe FL-16 in 2006 (when he couldn’t overcome the handicap of having to ask voters to vote for Foley, who could not be replaced on the ballot).
But Labrador is not merely of PR descent; he was born and raised in PR, and didn’t move to Nevada with his mother until he was 12 or so. The only PR-born Republicans who have won GOP House nominations in the past decade were, unless I’m forgetting someone, Jesus Caquias in TX-27 and Perfecto Rivera in WI-04.