As a matter of fact, I think I have seen in the box cardboard stock buildings on Ebay. Many thanks. Hmmm...I wonder if I have asked this same question before? 
Thanks to your recommendation I also love those weights and they fit perfectly in the "C" cell battery cradle and give the perfect "lift" for a "AA" to fit nicely. It also makes up for the lost weight of not using the big "C" battery and the really aren't that expensive. For example, these are where I purchased mine from... HERE. They do sell them in different quantities and there are also some that are selling lead weights although I don't recommend them.
Thanks to your recommendation I also love those weights and they fit perfectly in the "C" cell battery cradle and give the perfect "lift" for a "AA" to fit nicely. It also makes up for the lost weight of not using the big "C" battery and the really aren't that expensive. For example, these are where I purchased mine from... HERE. They do sell them in different quantities and there are also some that are selling lead weights although I don't recommend them.