Akai S1000 / S1100 samplers

Hi all,

I just noticed an odd thing regarding the S1000 apparence: some units
have the numeric buttons in light blue like this:

http://www.gbaudio.co.uk/images/s1000.jpg

while others have them in white, like the one pictured in the main
window of this group and here:

http://www.soundonsound.com/sos/aug05/images/sciencehakais1000.l.jpg

Does anyone know if different models came out with different specs
other then different OS versions?
Is the blue/white buttons just a cosmetic difference?

Regards

M.