Bodies and necks are made as a 'matched' pair. You'll see a number (eg. 19) in the neck pocket of the body and on the heel of the neck showing they were made to fit each other. 'Unmatched' is a general neck for a particular kit model that should be a close fit, but not made for/matched to a specific body. Generally they'll be a reasonable fit, but may not fit quite as well as a matched neck. Emphasise the may. I wouldn't hesitate if rosewood was my preference.