Rear shocks differences

[seth]

I know the early silver springs and the later have red springs .
But what I never noticed even on 2 of our bikes is that the gold remote reservoir on the red spring shocks are different lengths inside .
On emma's k5 it's about 10mm to the bottom of the reservoir and in the k6 that are almost flush.
Anyone got and incites to this and does it make any difference they do have different part numbers .
I'm wondering if one us an earlier set with red springs but both bikes were brand new when we got them .
Cheers