The main problem here is that signature is malleable. Given signatures on $m_1$ and $m_2$ allows you to construct a valid signature on $m_1m_2$ by multiplying the signatures. Therefore, the answer is no. When you hash you don't have $H(m_1m_2)=H(m_1)H(m_2)$, so hashing destroys this algebraic structure that connects messages and signatures.
EDIT: I'm assuming the question is whether you can sign without hashing when the messages to be signed are already intergers modulo $n$, i.e. you don't need to hash your messages to make them elements of this group.