Oregon "Gator" Mower Blades

Oregon blade #596-327, which is a Gator mulching blade that measures 15 1/4 inches long, 3 inches wide and has a round 5/8 inch center hole. Purchased for my mower but discovered that the 3 inch wide blade is too wide for my 3 blade mower deck. I have 3 but one center hole was widened to 3/4 inch on a blade to match my deck size. These sell for $31 per blade at Walmart. I'm selling less than half price.