I can't say with certainty what year H&B started making maple bats for MLB use, but the earliest order I can find is for Mike Matheny on August 22, 2000.
Until 2004, maple bats were labeled and branded just like ash bats. In 2004, H&B started putting the maple leaf logo on the reverse and either printing the trademark (Select Maple) or using a sticker (M9 Rock Hard Maple). 2004 also is when they started foil-stamping or laser etching the barrel instead of branding.
Jeff
http://www.birdbats.com