Sounds like the Cab Lights you have are "Fireman's Hat" style, which were pretty common in '72. I believe they were optional on any size truck, although the Heavy 2 1/2 to 3 1/2 Ton trucks got the Yankee 77 type. If the Side Lights are just the "Plain" style, they may be correct for your truck. I would check the Door Jamb Tag to see what GVW the truck has.
Welcome to the site, by the way.
Bill
