Eli Manning -- Let's Talk Body Hair ... To Shave or Not to Shave?

Ever look at Eli Manning and think ... "Hmmm, wonder if that guy shaves his chest hair?"

Well, good news -- WE JUST FOUND OUT!!!

Eli and his father, Archie Manning, were at Rockefeller Center in NYC this morning -- when we asked Archie to reveal the best Father's Day gift he ever got from his super famous kids.

Long story short ... we got into personal grooming habits ... and that's when Eli revealed what he's packin' under his shirt.