Your MV1 or MV4 pink slip is your temporary card for 90 days. If the dealer processes your registration, ie they gave you a plate, or transfered your existing plate they will process it.

To answer your question. If you bought a used car the title number is in the very first box of the pink MV-4 form they gave you at delivery.

If its a brand new car you would have been given a pink MV1. It won't have a title number yet because there are no titles for new cars, only MSOs, and the title number will be assigned by the state once they recieve the MV1 from the dealership.

They dealership has (typically) 15 calendar days to process your registration with the state. The dealership then prints out your registration card and mail to you.

If I was you, I'd call the dealership around the 30 day mark and see what's going on, you should have it then.

If you end up doing that form you are talking about and somehow it gets to the state before the dealership processes your title work, then you will have wasted your time because the title is going to be in the previous owner, or the dealership, or if new still on an MSO. And the state won't process anything.