before responsive design we need mobile specific sitemaps, but with responsive design they were not needed.
But with introduction of Accelerate Mobile Pages (AMP), we are again having mobile specific URLs, so my questions are:
No need providing you have a rel="amphtml"
link in your regular page to tell crawlers the AMP HTML version as discussed here:
https://www.ampproject.org/docs/guides/discovery.html
Similarly your AMP pages should have a rel="canonical" link to point to real page, to avoid search engines thinking you have duplicate content.
In fact for Google, in the Google Search Console for you site there is an AMP section (under Search Appearance section) that shows all AMP pages it has found and if there are any problems with them.