I think a bit of "outside the box" is required here... uname -a might be the answer.
PW: Linux kindle 2.6.31-rt11-lab126 #1 Mon Apr 1 22:09:02 PDT 2013 armv7l GNU/Linux
Touch: Linux kindle 2.6.31-rt11-lab126 #1 Wed Dec 12 19:58:30 PST 2012 armv7l GNU/Linux
K4: I can get this
K3: Linux kindle 2.6.26-rt-lab126 #5 Wed Sep 15 19:25:13 PDT 2010 armv6l unknown
K2: (niluje posted this somewhere... damned if I can find it)
DX: and this
Working on filling in the blanks now... tomorrow
(The date/time is unique on them all as a hint. I would go with that)
EDIT: Plus it doesn't change AFAIK.
Last edited by twobob; 05-14-2013 at 10:43 PM.