Very few 1500s came with the 3.92 ratio, but it was an option if I remember correctly. Most, if not equipped with the Off Road package, came with 3.55 gears. Off roads came with 4.10s, as previously stated.

The Sport editions are no different than regular as far as gear ratio goes.

Check under the hood, or if thats inconvenient, send the Parts and Service guy above the VIN. You should also do a CARFAX or similar on it with the VIN, if you haven't already.