There are a couple of Q/A posted on eBay for this item. One person notes that:
"This diamond-shaped pin belonged to a defunct local--one of at least four locals (independent fraternities not affliated with the Alpha Phi Omega National Service Fraternity founded in 1925) that operated at local colleges around the U.S. before the existing APO coed fraternity bugeoned and incorporated as a non-profit, scouting/service college Greek letter organization (GLO). More info at
www.apo-epsilon.org "