As long as the reinstatement was processed and accepted by the insurance company you should have coverage. In addition, you obviously need to have physical damage insurance on your car.
Some companies require that a no-loss form is signed. This form states that you haven't had any loss between the time of cancellation and the requested time of reinstatement. If you hit a deer during that period, then you would not be covered.
The easies way to find out if you are covered is by submitting the claim to the insurance company.