Yes, on a 1997. I replaced the switch, there are two wires which
operate a small magnetic solenoid to allow removal of the key. If
those are not connected you can't get the key out.. I learned this
after it was all back together :-) with the two wires not connected.
http://www.howstuffinmycarworks.com/GM_truck_bad_ign.html
Procedure on the 2000. The steering wheel should not have to come off,
but you do have to remove both covers on the column. Disabling the air
bag is not a bad idea either. Google for that procedure.
You will need some reverse-torx bits. I bought a cheap set of reverse,
normal, and security torx for about $15 at Harbor Freight.
My 97 got to where it would simply shut off while driving - sometimes
exciting. Replacement of the switch solved it.