Not the same. EL stands for "Extra Lusso" which translates to "Extra Luxury. It is a Beretta designation for higher end guns. Beretta like many gun makers will often put fancier wood on the first guns in a production run to make them more appealing. Therefore early DT11s will generally have nicer wood than later guns. Note if you are buying a gun online advertised with an EL stock make sure you get pictures of BOTH sides.
As you noted, Xtra Grain and Xtra Wood are the film finishes are found on less expensive guns. Beretta marks the stocks with this finish which helps prevent unscrupulous gun dealers from attempting to pass them off as real wood. I've called out a couple of dealers who tried it including a prominent site sponsor.
Xtra Grain and Xtra Wood are like breast implants. They look pretty good from a distance but up close and uncased anyone with a little experience can easily tell they aren't the real thing.