Claptrap was a unique case of wholly thought out design. He is Hyperion, so he had some loader abilities to consider when it came around. Wilhelm also had an armor as health skill. Fl4K is more like Zer0. A humanoid style robot. It would be cool, but it wouldn’t make as much sense as a skill, and as an inherent ability; it wouldn’t be the best for a sniper. You gain a guaranteed death dot (corrosive hits much longer on armor) for a couple of minor damage reductions while getting ganged by 6 Fanatics. It’s okay at best. Why aren’t you farther away so you don’t need armor, Sniper bot? (gameplay wise)
Either way, no, he has flesh like all VHs before him. It wouldn’t really matter even if he did. It gives him no real bonuses as compared to Fragtrap, which as a grenade and Explosive user, saves his ass.
Maybe I’m wrong though. Could be a great skill.