For an arbitrary $K$-algebra $R$, an $R$, $K$-bimodule $M$ is algebraically reflexive if the only $K$-endomorphisms of $M$ leaving invariant every $R$-submodule of $M$ are the scalar multiplications by elements of $R$. Hadwin has shown for an infinite field $K$ and $R = K[x]$ that $R$ is reflexive as an $R$, $K$-bimodule. This paper provides a generalisation by giving a skew polynomial version of his result.