well, i guess anything google these days is possible, but if it's duplicate content i cannot imagine where it's coming from. it's all original content. it's a small 1 man site that sells books. some terms naturally may occur in more than one listing on a page, such as "page" or "history" or whatever. the only duplication i can possibly see is the info on the "product detail" page for 1 product is also in the listing pages of 10 items per page.