I have always thought that the Post cereal cards were relatively easy to counterfeit given the coarse cardboard on which they were printed, a simple design, and the fact that they are hand cut.  I have not been able to find much information about this, however, and was wondering if anyone has any insights.  This listing, for example, almost looks too good to be true:
http://www.ebay.com/itm/1963-POST-CE...:SS:SS:US:3160 
Any thoughts are greatly welcomed.
Ed