  Let $(M,\mathcal{N})$ be a marked 3-manifold. We use $S_n(M,\mathcal{N},v)$
to denote the stated $SL_n$-skein module of $(M,\mathcal{N})$ where $v$ is a
nonzero complex number. We establish a surjective algebra homomorphism from
$S_n(M,\mathcal{N},1)$ to the coordinate ring of some algebraic set, and prove
its kernel consists of all nilpotents. We prove the universal representation
algebra of $\pi_1(M)$ is isomorphic to $S_n(M,\mathcal{N},1)$ when $M$ is
connected and $\mathcal{N}$ has only one component. Furthermore, we show
$S_n(M,\mathcal{N}',1)$ is isomorphic to $S_n(M,\mathcal{N},1)\otimes O(SL_n)$
as algebras, where $(M,\mathcal{N})$ is a connected marked 3-manifold with
$\mathcal{N}\neq\emptyset$, and $\mathcal{N}'$ is obtained from $\mathcal{N}$
by adding one extra marking.
