Probably an old Collegiate back from when they were distributed by Miller's. They made a special Olympic Edition at one point.
Check out this one that was on eBay
to see if it's the same: http://cgi.ebay.com/USA-Olympics-Sad...QQcmdZViewItem
These saddles were made in Argentina. The RD on the plate stands for Ruiz Diaz who now makes Pessoa saddles in Argentina.
Anyways, if this is the right saddle, good luck finding one! They are not made anymore since Miller's went out of business. And it was a special edition, so there probably weren't that many created. It's possible that other Collegiates may be similar...like just made with different leather or something.
*edit* Now that I looked closer at that eBay listing, I see that the auction didn't actually sell. So, if you'd be willing to pay $750 for it, I bet you could contact the seller and get them to relist it for you.