I believe it is. I have what looks like th same plant. I purchased it as Echinodorus amazonicus, Amazon Sword. It has narrow leaves and the info I found says that it will stay smaller if given less room, no CO2 and limited nutrients.I bought some plants today labeled as Amazon Narrow Leaf, but when I look at online images they seem to look a little different.
What plant is this?
Here's a link to some info for it. http://www.plantgeek.net/plantguide_viewer.php?id=84