So I looked up the weapons possession charge, and it seems like Maduro could be guilty under the statute of her possessed a machinegun (really any full auto firearm) in furtherance of the drug trafficking activity. Even if the weapons were only possessed outside of US jurisdiction.

Short version: the "possession of weapons charge" is actually for possession while drug trafficking.

I don't know if they have to prove that Maduro physically handled a weapon or not. But if they do, and they don't have that evidence, he could still be guilty of the subsequent conspiracy charge.

Edit: For the avoidance if doubt, the drug trafficking is very important to the whole case, because that's what gives the US courts extraterritorial jurisdiction.