To be honest, there are instances where GPAs have been rounded up. This doesn't happen for every chapter and there are organizations with chapters that are more prone to round up than others. It's a factor of the GPA distribution of the pool of applicants, the GPA distribution of the chapter, and what the chapter (and local and national offices) will tolerate. BUT, WE CAN'T FORESEE THE FUTURE AND TELL YOU WHAT THE OUTCOME WILL BE IN YOUR CASE.
Disclaimer:
Grades are extremely important and there are unfortunate circumstances where students don't reach their maximum potential (i.e. family problems, illness, depression, etc.). There are also circumstances that are completely within the student's control (i.e. laziness). The key is to address these issues and reach a better YOU so that you can hopefully reach membership in a frat.

A lot of people have to wait to pursue membership or don't get accepted the first time(s) they try. There's a reason why NPHC orgs don't restrict applications on the basis of year in college and age during and post-college. Just know that your GPA will still be a factor if you wait a couple of years and pursue graduate/alumni membership. Good luck.