Well maybe.

There are monolithic uppers, uppers that are the upper and the rail system all in one. One big piece of metal. VLTOR makes a monolithic upper, and LaRue is rumored to have one in the pipe.

Then there are railed handguards that are not part of the upper but connect to it in some matter or fashion.

But it is all about marketing. So I suppose that you could make a product and call it integrated. Or it could integrate certain features that others don't or something.