Morris Cooper and S grille.
The wide slats are made in automotive type 430 stainless steel which means any stains created where it would attach to ordinary metal can be polished out. If you fit an internal bonnet locking kit there is a grille 24A2159 with full top slat - this grille with correct surround is often fitted to later cars for the Retro look.
On production cars a chrome over brass grille with a slanted bottom slat was fitted (24A152). This lower slat was changed to a rounded edge as per other slats to comply with safety homologation laws in late 1965 and fitted from Jan 1966 on. The lower pointed slat was deemed as being potentially dangerous to cutting fingers when washing the car.
The new grille 24A2158 was fitted to cars in 1966/7 and all subsequent spare parts sales by the factory. Although drawings show aluminiumAL/T2 as an alternative material they were only made in automotive s/steel.