Available at 1/35, 1/72 and some of them even at 1/48, Rescue Models has front grills in different variants for GMC CCKW, Studebaker US-6, Dodge Beep, Willys and more.
This is a small selection of products, check their webshop at www.rescuemodels.com for the complete list.
1/35 Studebaker US-6 asymmetrical front grill for ICM
1/35 GMC CCKW 352/353 asymmetrical front grill for Hobby Boss
1/35 Sd.Kfz. 222 roof grill for Hobby Boss
1/35 M1A1 Abrams exhaust grill for Dragon
1/35 US M19 front grill for Merit
1/48 GMC CCKW 352/353 asymmetrical front grill for Tamiya
1/72 Chevrolet M6 rounded front grill with (side) blackout light for Airfix
1/72 Autocar U-7144-T front grill for Airfix