Yes. Zoro obviously has no Haki on his blades, while Kaku is a known Tekkai user (which is basically CoA application). We know swordsmanship shines most when imbued with Haki, as Ryuo allows you to "cut everything" and Haoshoku massively boosts the cutting capability too, while we haven't seen Magma being infused with Haohsoku. I mean, Jinbe blocked Akainu's magma fist with his palm. It was damaged, but it was still his palm.