You can "download" crappy, not very effective guns. And you still need to obtain the ammo (the actually lethal part) the old-fashioned way.
I would very much be surprised if it becomes possible for drugs or explosives any time within my lifetime. Chemistry and physics just don't work that way.
Still, you do need very specific input materials for both processes.
In the case of the latter, you basically need a spool of explosive string. You're not so much printing an explosive as you are shaping an explosive into a desired form. I'm sure it's still very useful, but I don't think it's a particularly big game changer in the "smuggling things into a country" field.
I would very much be surprised if it becomes possible for drugs or explosives any time within my lifetime. Chemistry and physics just don't work that way.