http://www.ebay.com/itm/291197776572?ru=...6572%26_rdc%3D1
I have several pictures of 480's with large 0's. Don't know if 9D28 is a known date for a 480, but it is for a 499, and the date stamping is real if that is a viable date for a 480.
I asked about the numbers on the bottom of the weight plate. I'll post back if I get a reply.