@gster123 - Knew I should have posted this earlier. I was thinking the same thing.
I think Dave means that the Undo List is nuked when you exit maya, as opposed to the Construction History. Just loose use of terminology.
Another way of doing it is to open the object in the attribute editor, same as 99gsturbo's reply, you need to still have the object's construction history intact. If you select the tab called polySmoothFace1 or equiv, open the part called "Node Behaviour" you can change the NodeState dropdown box to Has No Effect. (Noe this has provided some with probs in the past, i.e selecting "Has No Effect" has no effect:p )
If you then copy the result of either way of doing it, you've got a nice, clean low poly version again.