Cognac,
The information is freely available on the QF LAN (if you have access. If you dont any QF LAME at AVV will have.) Search the G drive for the HMPlan folder. Once there search the 2005 archives to see when the XM series entered the plan. It's all in excel format. You will see the original start & completion dates with some fat padded in on the first one for obvious reasons.
Cheers,
Rmm