I have a '73 GMC , but I don't know what model it is. I know it is a 1/2 ton, 2whl drive. 350 4bbl carb. It has a Tachometer, power windows, power door locks, cruise control, tilt steering, I think the power windows and locks were added in after cause I heard they weren't available til '78, is that true. Can anyone tell me if this would be a Sierra, Sierra classic, or High Sierra? Or even a website that describes this stuff in detail. Thanks for any help, much appreciated. I need to know what emblems to buy for this as I am restoring.