Posted By:
warshawlawthen don't worry about it; a pricing error isn't going to hurt you much.
If you think that the item will rise precipitously in the future, you may want to hold it. If not, I think that 2x book on others is as good a starting point as anything else.
Of course, you also have to consider that uncatalogued has a way of becoming catalogued rather quickly in this instant information age. I have dozens of uncatalogued cards; doesn't mean I think they carry any real premium on them.