Two bits of advice.
First, the allinanchor is a definite indicator of where the site will rank once out of the sandbox. If you are seeing an allinanchor of #1 and real rankings at 450, it is buried in the sandbox. The previous post about 450 equalling out of the sandbox is not true. Gambling sites do seem to spend a very long time in the sandbox, we are out for a few less competitive terms, slowly coming out for the medium competitive terms and buried for the very competitive terms. 2 years and counting BTW.
Second, in the case of duplicate content, it’s not the case that the originating site gets credit for the content. Google will assign the owner of the content based on the strength of the sites containing the content. So, if the offending site is stronger, then they would get the credit for it, and your site could potentially have the duplicate pages removed from the index. If the pages in question are cached by Google then you should be fine.