It certainly makes more sense than storing them globally, but making the print setting persistent per document seems to me to be a change that should be made globally across all relevant Gnome apps or not at all. It doesn't make any more sense in evince than it does in OpenOffice.org or any other app that prints documents, so for the sake of user comfort I think adding this feature just to Evince would be confusing.
It certainly makes more sense than storing them globally, but making the print setting persistent per document seems to me to be a change that should be made globally across all relevant Gnome apps or not at all. It doesn't make any more sense in evince than it does in OpenOffice.org or any other app that prints documents, so for the sake of user comfort I think adding this feature just to Evince would be confusing.