GMguy,
The answer is no. The wheel base is longer on the xi series versus the older 300, 400 and 500 series gt's. I own a 2004 520xi. I traded in a 1998 314-8 towards the 520xi purchase. My 314-8's front blade was to short to fit up properly to the 520xi, and the snow blower has a different pto pulley setup between the two models.
The same attachments do interchange though between the older 300, 400 and 500 series gt's. I'm not sure if an older model rear clevis hitch will interchange with the 520xi???