You had an unusual Silver Hawk.  By the way, it was a 57 not a 56.  It is unusual in that while all Silver Hawks were "pillared" coupes, i.e., had a post or B pillar between the front and back seats, yours was a true "hardtop" (no pillar).  The only Silver Hawks that were produced as true hardtops were export models.  Not sure how many export models were made but it couldn't have been many because TOTAL Silver Hawk production in '57 was only 15,318.

You can tell I have time on my hands on a rainy day.....