Pete,Bruce hit six triples in the major leagues. His final triple came in the Mets home opener on Tuesday, April 10, 1979 against the Expos. The game was tied 2-2 in the bottom of the ninth. I assume this is what you were referring to..I will plug in the narration from retrosheet.com:
METS 9TH: SOSA REPLACED HUTTON (PITCHING); Flynn was called out on strikes; BOISCLAIR BATTED FOR SWAN; Boisclair tripled to right; Mazzilli was walked intentionally; Boisclair was caught stealing home (catcher to third) [Mazzilli to second]; Chapman grounded out (shortstop to first); 0 R, 1 H, 0 E, 1 LOB. Expos 2, Mets 2.
The Expos won the game, 3-2 in fourteen innings.