Hi climbingupup,
Considering that the process of receiving Official Scores from GMAC is a standard process, it's is not 'normal' that the School would ask for your Unofficial Score data.
How long ago did you take the Official GMAT? If, for some reason, your Official Score Report was not available to that School right now - and the School wanted to make an immediate decision on your application - then seeing your Unofficial Score Report might be all the information that the School's Admissions Committee would need to do so. I suppose it's also possible that the School has some reason to question your Official Score Report and is looking for a second source to confirm that data - although I thing that would be rather unlikely.
GMAT assassins aren't born, they're made,
Rich