Actually, the Jalpa was the Silhouette's replacement. It had a bigger engine, better interiors, different fender flares, wheels and engine lid. But the chassis and suspension are basically the same, and they both come from the Urraco.
Rocky's car was a Jalpa.
The Silhouette is very rare. Only about 50 Silhouettes were made in '76-'77. The Jalpa was made from '82-'88 and about 400 were made.
Thanks,