C/K is actually a letter from the VIN... C denotes a full-size 2wd truck. K denotes a full-size 4x4.
S/T trucks (which everybody just refers to as S10 trucks) An "S" truck actually means a small-sized 2wd truck. A "T" truck is a small-sized 4x4 truck. So to say "I have an S10 4x4" is really a double statement. "S" meaning 2wd and then desribing it by making clear it is a 4x4 as well. Just the way things are. The part below where you have "C/K Pickup/Suburban" is acurate but the Jimmy part doesn't make sense, unless this manual tries to cover a little of all models...
Long story short, purchase which ever manual supports your vehicle best..
HTH
Nick
I am purchasing a 1989 GMC Sierra truck and I'd like to pick up a
> repair manual for it. The truck is listed as a GMC Sierra K1500. I
> went to various online retailers for service manuals and all have two
> "model" options. One is simply for Sierra and for this model, the only
> manual that is offered is the original owners manual. The second
> option would be "C/K Pickup/Suburban/Jimmy" which has a much longer
> list of available manuals. Would the manuals listed under the C/K
> model be what I'm looking for...aren't these in fact the same truck? >
> Kevin