https://www.theautochannel.com/db/usedcarbuyersguide/list_trims.php?bodystyle=Fullsize+Pickup&make=Chevrolet+Truck&model=Silverado+1500+Regular+Cab+2WD&myear=2004
Used Car Buyers Guide: Search for a car by trim
The Auto Channel Used Car Buyers Guide provides searching for a used car by trim.
used car buyers guidesearch fortrim