VINTAGE 1950's Toy MARX Lumar Military Army Truck Mounted Rocket Launcher

Thanks for looking at this MARX Lumar military army truck FOR PARTS OR RESTORATION. Looks like batteries were not left in unit. Untested motors; look pretty clean. One of the big rollers for R track broken off as shown. Metal body; gray body of launcher and radar are plastic. 3 darts; dart tips as shown. Big gun photo with ruler points to a ? broken part. Bought at an estate sale. Feel free to ask questions.