#3 - Dec. 11, 2008, 4:34 p.m.
Mail and plate heirlooms behave a bit differently than other pieces. These heirlooms' armor type will change once the character reached level 40. For example, [Prized Beastmaster's Mantle] are considered leather up until level 40; once the owner reaches level 40, they transform into mail shoulders and their stats will be updated accordingly. :)
Enjoy!