[Flyndaran]

It's that he has an upper layer of biomimetic flesh-like material with No Signature, so it looks like normal naked human tissue. But under that he has a flexible "leathery" armor protecting his actual internals.
Any damage penetrating the "flesh" will reveal his obviously armor.

If both sets have No Signature, then damage would have to penetrate both layers to reveal his nature.

If only the top layer needs it, then it would be easy to munchkin by taking a single point of DR that way. Creating a costume looking unarmored when normally one would have to spend loads of points to make all of one's armor have No Signature.

Does that make my point any clearer?

I just felt that Ablative may make the idea less Munchkin friendly as it create an extra "hassle". I'm probably over-thinking that part, so if it helps, you can just ignore it as extraneous to my main idea.