Once you get into a specific MBA program, your resume will get published in a resume book for campus recruiters.
Students who scored high in 700 range will probably post their score on their resume. Plus, specific employers have GMAT score section to post in their online application. (i.e. - Goldman Sachs)
GMAT score can be used as a comparison tool by a potential employer and he/she can even bluntly ask you your GMAT score during the interview.
Therefore, yes-------it CAN matter once you are in school ---- in many different ways other than the examples used above.
P.S. - 690 is a fantastic GMAT score. It's up to you if you want to put little more effort in and break the 700 barrier.