I checked the others.
|Ray Boone 1953|
by Bowman Gum
via Wikimedia Commons
In 1998 Piazza hit three for the LA Dodgers (two on consecutive days) and one for the Mets. Piazza hit 14 career.
Too bad Yank researchers didn't look a little further.
I also noticed that Boone led in RBI one year. His grandson Bret Boone also led in RBI. I wonder if they are the only grand (father/son) to lead in the same major batting stat.