If I go with an initiative 1 weapon, I usually go Hammer. That said, I bought both new models. I'm a sucker though.
I think he meant just a modelling choice rather than an actual piece of wargear. It seems silly that even a Marine wearing huge gauntlets for a Power Fist or Lightning Claws could pull the pin and throw a grenade. Instead of that if he was modeled with an AGL it makes more sense how he "throws" a grenade.