I'm looking at buying a used truck. The dealer doesn't have the build sheet. How can I verify optional equip was installed if I don't want to take their word for it? Specifically: It's a 2005 Nissan Frontier Crew Cab 4WD LE. The option is MFR Code B01, 4 wheel Limited Slip with Active Brake Assist. Since I can't see it how do I know it was installed? Thanks so much for the assistance!