You might be onto something. In TOS he melded with Dr. Gelder to get information. That's not what he was doing with Kirk here in SNW. So technically, he hadn't melded to obtain info with a human before in TOS. It barely fits, but it works, sort of. Perhaps Vulcans are more exacting about how they label these techniques that are performed than us humans who just label them all "mind melds". In fact, the word mind meld isn't even used in Dagger of the Mind, just "ancient Vulcan technique".There's a difference more obvious to Vulcans between connecting to coordinate thoughts and actions and connecting to search thoughts. He's never used that particular melding technique on a Human.
As an example of what I meant, you may have painted on a canvas before, but always with a brush, never my fingers or a paint sprayer. You may have sung before, but never opera or yodelling, always choir singing.