Site Map index and robots.txt referencing .gz files

For a website, my Site Map Index file and all my Site Maps are gzipped and have names like the following (SiteMapIndex.xml.gz, SiteMap1.xml.gz, SiteMap2.xml.gz), should the robots.txt file and SiteMapIndex.xml file have references to the gzipped file name or non-gzipped file name?

Example -Should robots.txt contents look like this? -

Sitemap: http://www.mysite.com/SiteMapIndex.xml.gz

or like this (without the .gz)?

Sitemap: http://www.mysite.com/SiteMapIndex.xml

Should SiteMapIndex.xml contents look like this? -

...<sitemap><loc>http://www.mysite.com/SiteMap1.xml.gz</loc><lastmod>2013-08-20</lastmod></sitemap><sitemap><loc>http://www.mysite.com/SiteMap2.xml.gz</loc><lastmod>2013-08-20</lastmod></sitemap>...

or this (without the .gz)? -

...<sitemap><loc>http://www.mysite.com/SiteMap1.xml</loc><lastmod>2013-08-20</lastmod></sitemap><sitemap><loc>http://www.mysite.com/SiteMap2.xml</loc><lastmod>2013-08-20</lastmod></sitemap>...