860=Last 2 digits are range 60=stability, first digits = how high up the range so 860 is a higher model than a 560
RS2/SB2 etc= Colour codes, RS2 is the red and silver version for example
and yes, SS12= Spring/Summer 2012
In the NB range 00 is minimalist/barefoot, 40 is motion control (high stability), 60 is stability, 70 is lightweight stability, 80 is cushioned, 90 is racing series.
I hope this helps!
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