Hi Zack,
Great question. First of all, I haven't gotten to play with the official AMP plugin for Wordpress yet, but I've been researching and reading about the implementation of AMP pages within Wordpress for a while now.
First of all — it's recommended that you utilize AMP pages if you are a publisher or push out content often. In other words, AMP is not ideal (yet) for ecommerce, casual bloggers, etc. You can definitely try it out, but AMP was specifically designed for publishers that churn out a lot of content.
To answer your question regarding duplicate content — From my understanding, the proper way of implementing AMP pages and avoiding duplicate content is to put a canonical tag on your main page that points to the AMP page (this way Google sees that you have an AMP version of this page), as well as adding a canonical tag on the AMP page that points to the regular page.
In other words, you would have something like this.
Main Page
AMP Page
Here's Google's take on this.
i'm assuming that the plugin will automatically add the correct code to the pages, but I have not tested it so I wouldn't know for sure. Please do let us know if you end up testing this out!
Also, you might want to check out Yoast's "Glue" plugin for editing and adjusting AMP pages. It seems like it could be helpful.
Cheers