nope, i know a greek orthodox woman who wears hijab for her religion. lots of people wear hijab like head coverings from india to ethiopia. nuns also cover their hair.
different hijabs don't mean different parts of islam, anyone can wear any they want. the more religious ones wear burkas and niqabs which cover the face. the style that is most worn changes from place to place, in egypt most girls just wear a small headscarf with jeans but in somalia, religious girls wear jilbaab in bright colors. muhajabat.files.wordpress.com/.../somaliwomen.jpg