Should I attend counselling at IIT Guwahati for an MTech in mechanical admission?

MTech in Mechanical Engineering comprises various specializations. The cutoff for each specialization varies. Usually, the highest cut-off is for machine design then fluid and thermal science followed by CAM and computational mechanics. If you are attending the counseling you have to specify the preference order among these four. So depending on your rank, you might get admission to a specialization you did not want to study. 

I recommend that you attend the counseling and don’t make assumptions beforehand. Sometimes the wrong train leads you to the right destination. It’s better to explore all options to determine what’s best for you.