Riding Lawn Mowers

I purchased a Husqvarna YTH22V42 Lawn Mower on 06/14/10. The serial number on the Mower is 051010A002128. The Briggs & Stratton Intek 724cc 22 HP Motor has a build date of 06/2007 & the Serial Number is 070610YG68732. The dealer said that the engine being 3 years old didn't matter. What's the deal. Motor sits in a warehouse for almost three years before it's installed in a mower.

Johnny Chambliss