An Artificer Armorer acquires the class feature "Arcane Armor" at level 3. With that, the armor provides a special simple weapon (Thunder Gauntlets or Lightning Launcher). Now all of this "Arcane Armor" is one entity (from the perspective of infusions). This changes when you are level 9, then you acquire the "Armor Modifications" class feature, which lets you count your Arcane Armor as four different entities (again from the perspective of infusions).
Can you apply a weapon infusion (Enhanced Weapon) to the special simple weapon (Lightning Launcher) before you get "Armor Modifications" as early as level 3 if no other infusions currently affect the Arcane Armor (no Enhanced Defense, etc.)?
I have seen another post regarding whether or not you can infuse the weapon when you hit level 9 with "Armor Modifications". I am asking explicitly can you do this without the "Armor Modifications" class feature.