Hey SB, BBA is an undergraduate course so according to my experience your college wont matter much. IBMR Gurgaon is a much better college not only  because of its academics but also the exposure that it will provide. You can even take into consideration the perks of being in Gurgaon a place where you will have maximum exposure if used properly. The best coaching institutes for the preparation of MBA is in Delhi only so that will also be very beneficial for you. Therefore I would suggest you to prefer IBMR Gurgaon over Guwahati University.

Best wishes