Yes, this is true: the smooth minimal model is a $K3$ surface. In fact, let $\bar{X}$ be the resolution of the singularities of $X$. Then the following holds. **(1)** Rational double points impose no adjunction conditions to canonical forms, hence $\omega_{\bar{X}}$ is trivial. **(2)** Rational double points have simultaneous resolution, hence $\bar{X}$ is deformation equivalent (and hence diffeomorphic by Ehresmann's Theorem) to a smooth complete intersection $X^{sm}$ of the same type as $X$. This implies $b_1(\bar{X})=b_1(X^{sm})=0$, hence $H^1(\bar{X}, \, \mathcal{O}_{\bar{X}})=0$. For part **(1)** you can look at M. Reid's *Young Person Guide to Canonical Singularities*, whereas part **(2)** can be found in Kollar-Mori's book *Birational Geometry of Algebraic Varieties*.