The hamon on a differentially tempered knife wouldn't be a stark contrast like on a custom made knife with higher carbon and an acid etch, but the more tempered spine-side reflects light differently than the more hardened edge-side.

Even with a mindset of toughness-uber-alles, I can't see anyone differentially tempering S7. If Dan does that, my statement is literal as I ain't in Tejas.

"I knew you before you knew you had hands" ~Tracey Brogan