I would say this is true, Apple has laid the differences out nicely for us:
http://www.apple.com/iphone/compare/
Keep in mind, what Apple has not told us yet, but folk have noticed in their YouTube (the MeFirst) testing is that they applied several mechanisms to make the 6s water resistant. Obviously they're not ready to have anyone hold it up to the light and analyze, but there is a new rubber gasket around the edge of the phone and every chip has a new (apple patented in March of '15) water resistant protective device installed around it. The SE does not have this.