There were several hardtop options available for the SC and 3.2 cars:
1. The hardtop as per the above post. Option code # 550.
weight 73 pounds, cost US$2400, and the "stand alone" part,
which is no longer avaiable.
2. Also, the Targa non-folding hardtop.
Somewhere???, I have more detailed pics of an SC car with the top on/off
which I took at the Ludwigsburg show room.
Maybe 911kiwi will post a few.
Also, as per the above post, a retrofit would be a bit "intense".
Best,
Gerry