Corrected entry: In the desert shootout scene Murtagh throws what looks like an M67 "baseball" hand grenade on the ground. They wait for it to explode and Gary Busey says "it's a smoker". M8 smoke grenades look like a soda can, nothing like the baseball shape of a live M67.
stiiggy
20th Aug 2020
Correction: First, the grenade shown is more like the M61 "lemon" grenade. And there's no telling if Murtaugh/Riggs obtained a M61 based smoke grenade perhaps from a military surplus store that added the smoke effect for realism without the bang, or even a home made by Riggs grenade for this purpose, as opposed to using actual US Military M8 smoke grenades.