X2503 Quad Loop

Hi to all. I have a D.C. that is a X2503 Quad Loop. 60" cut. And has a Kohler V-twin motor. Most of the stickes are off the unit. So I was wondering what was the years that this unit was made. I was told that it came off of the golf course and that it was a back-up mower. It was not supposed to have been used that much. I don't have the serial number because I'm at work now, but can get it later and post up. When looking at the D.C. website, no where does it say anything about a "Quad Loop" unit. So I'm thinking that this unit may have been produced in the early 2000's.
Thanks for any input with this limited info.
Hump.