At first glance , it looked like a vintage/antique paint-scraper (& I thought "Hmmm... maybe he's in the union & on strike ...") in his hand , but that wouldn't fit , even though he looks like maybe he got painted here & there a little after he left the factory (?) .
At a second glance , I thought it might be a fancy quill pen , for signing away large chunks of land ...
One-armed bandit handle would not be a fit either , nor PC @ all .
Perhaps what the fellow has got gripped so tight might be an atlatl , but that's a bit odd to use in a sitting position ...
I really think that it's a rattle , though .
Cool old toxic toy , KevinB !