You know she's making a movie about porn and she's laying down all these rules, maybe they should get someone else. Imagine a guy saying "yeah I'll play Jesse James, but I don't like guns so I won't use one in the movie." Linda Lovelace was a tragic story of an abused woman who performed sexually as a prostitute and as the first "porn star". Her career involved being naked and performing sexual acts. I would call that central to the character.
My guess is that a lot of extras are going to be naked instead. And I predict it now, this will be one of the biggest bombs of whatever year it comes out.
I'll watch the one with Malin Ackerman instead. She's gotten nude on film already, so chances are she'll show some in her version of the Linda Lovelace story. Seyfried is hot, but I think her days are numbered.