I bought this Kong bomb off someone here years ago (I think it was Tom Spina. He used a different name then.). It was said to be cast from an original, but I can't say for certain. Either way, I like it.
I have the same Gas Grenade. It wasn't Tom but a member that has since left the RPF. It IS definitely cast off one of the originals. I was at a convention in Washington which Forrest J. Ackerman attended and brought several of his original props. I photographed his original grenade and the wood pattern and chips all match up to this one.