Quickest way would be to use the hypershade. RMB on the original material, then select objects with material, you can then change it from there. A lot quicker than trying to select faces on a complex model. You could also use this method to separate it into various poly groups.
https://puu.sh/57aQn.png
bullet1968
"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes