The side fairings were changed for the "new style" MY '04 and later ST models so that they could be removed for routine maintenance items, such as adding oil, without doing a complete take down starting with removing the dash cover, then the side view mirrors, etc, like the MY '03 and earlier "old style" ST models.
LT sold a bracket so that the "old style" side fairings could be removed without a complete take down, so it may be possible to use a "new style" side fairings on an "old style" ST.