Hello Amanj,

If you have not applied or registered for a normal round of IIT in case of MTech, you are eligible for registration for the spot round. The difference in case of not having registered for the normal round instead of doing so, you are required to give the GATE entrance examination and have a valid GATE score with you. This will allow you to take admission by means of the spot round in MTech in the IIT that you would prefer. 

I hope this helps. 

All the best!!