Thanks for your help! We found it after all.
For people looking to customize this as well, here's the file you need to edit.
conf/battle/items.conf
Find this part here:
// Do produced items have the maker's name on them? (Note 3)
// 0x01: Produced Weapons
// 0x02: Produced Potions
// 0x04: Produced Arrows
// 0x08: Produced Holy Water/Ancilla
// 0x10: Produced Deadly Potions
// 0x80: Other produced items.
produce_item_name_input: 0x03
And replace produce_item_name_input: 0x03
to: produce_item_name_input: 0x07 (For produced Weapons, Potions and Arrows)