Don't spend your energy worrying about this issue. As long as a GMAT score is valid (ie, within the 5 years), it is an admissible score for an MBA.
I was previously the Director of MBA Admissions at a top 30 program. I often had undergraduate students come by my office to ask if they could be admitted to the program. After I told them to come back after they had 3-5 years of professional experience, I always advised them to take the GMAT while they were enrolled as an undergraduate student. You're in an academic lifestyle, and you take tests routinely. This is the optimal time to take the GMAT.
When I was applying for my PhD program, I had to take the GRE after 12 years of no academic work. I found it extremely challenging to re-teach myself mathematics and grammar to prepare for the exam.
I have another piece of advice for you as you plan for pursuing an MBA in the future. Go into this process with confidence and strength. Don't assume the worst of a situation, and don't be apologetic for taking the GMAT while you are an undergraduate student.
15 Years as Director of MBA Admissions - Now Working For the Applicants as the MBA Admissions Coach
Wendy Flynn is the MBA Admissions Coach, providing comprehensive MBA admissions consulting services. As the former Director of MBA Admissions for 15 years at a top-30 MBA pgoram, Wendy holds deep expertise in admissions issues for Full-Time, Executive and Professional (Part-Time) MBA Programs. Through her blog, MBA Expert Insights, she brings the view of the Director of MBA admissions to MBA applicants and others.
MBA Expert Insights Blog: http://www.mbaadmissionscoach.com/blog/
Member of the AIGAC, Association of International Graduate Admissions Counselors