Home » Mega Gallery: 2014 GMC Sierra at Spaceport America » 2014 GMC Sierra SLT Crew Cab in Iridium Metallic headlamp detail – on location 2014 GMC Sierra SLT Crew Cab in Iridium Metallic headlamp detail – on location Home » Mega Gallery: 2014 GMC Sierra at Spaceport America » 2014 GMC Sierra SLT Crew Cab in Iridium Metallic headlamp detail – on location