Cops are cool, as I have been one for 19 years. Most cops don't even know what 922r is let alone if your weapon is legal or not becuase of US made parts. As far as the Feds go, it seems like you could ask 10 ATF afents the same question and get 10 different answers.
First question, is your Benelli pre 922? If it is, you can do anything you want to it, except make it full auto. If it's post 922, then as long as you dont have a PG stock, you are ok with the 7rd tube, just cant have both. Hope that helps.