An article/letter in ToyFare magazine also confirms that random mistakes are by no means valuable. They're just freak mistakes. Remember that in order for something to be valuable it must follow the basic laws of supply and demand - i.e. low supply with high demand.

Freak mistakes like this are incredibly low in supply, this is true, but the demand for mispackaged toys is so negligible that it doesn't effect the market value of such toys. As dirge said, it's an interesting novelty item to have but it's by no means a really valuable collectible.