MapleStory Chaos: Profession Recipe Guide

No, that shoulderpad has slots, and can therefore be potentialed, the ones you make don't, so they can't. Those aren't the only things that can be potentialed, they're just the only ones you can make with Jeweler that can be potentialed, because they have slots.

This is correct. Check for slots if you want potential items. Of course, class specific items still cannot be potentialed, like Dragon Equips and Mechanic Equips.