Yes it is required. The usual time limit is 30 days from what I know to get NOC. But the problem would be to prove that you were in the parent state before those 30 days. Say on day 15th of going to a new state, a cop catches you, you will have to prove that you were in another state 15 days prior. How will you do that? I did it by using a bill from a petrol pump. But my parent state and current state are close by enough to do that for me every month. Will you be able to do it? Very difficult.
But NOC is rarely asked and they will most probably let you go. The usual under handed technique is what people do.
Best way to do this is to go to the RTO in your current state and get it done. You will have to give them a little money but it will save you lots of headache. Before 6 months, pay the road tax in the new state. Then you are good to go.
