Most dealers would do or add anything you were willing to pay for at that time. The Cornering Lights were more involved than you might realize. Changing the trim parts wouldn't be a big deal, but getting into the wiring could get involved plus the cost of the parts not to mention the labor wouldn't make it practical to most buyers. My '66 Impala SS I had the under hood and trunk lights added and they got that done in the time it took to do the purchase paper work so that wasn't a big deal. An example of costs think about their F41 Sport Suspension. This was a $30 some dollar option on an ordered car. This included a larger diameter front Sway Bar and a rear Sway Bar that a normal car wouldn't have had. In addition you got heavier Springs and HD Shocks. Talk about the buy of a life time, this was it.