it is. Or rather, they're all different names for the same basic art and concepts.
This has been talked about in endless threads on any forum that discusses FMA. Go to google.com and search for 'Kali Eskrima Arnis differences' and you'll find more than you could read. search at groups.google.com as well. Heck, even use the search feature on this board and I know you'll find a few threads on this.