The "2nd gear start" feature was an option, and while it's not rare, it wasn't super common, either. The picture bluegtp posted is what the button would look like on the '94 - '96 style interior. For your '92, if it came with the feature, it would be on the end of the center console (just below the Driver Info Center if your car has one of those). However, 2nd gear start only works with electronic transmissions, so the only w-bodies it would be optional on are all 3.4 DOHC motors, and '93 & up on everything else.
