Someone please correct me if I'm wrong, but a "Prima" MAY be a later model than the one linked by Whaler. The one in the linked eBay auction is the older S-6 Yanagisawa (which were also stenciled as Vito, Dorado 600, etc.). The S-6 was styled after Selmer's sopranos up to MKVI.
The later models had the modern pinky tables, forked palm keys, and over-hanging bell pads like the Yamahas and Selmer Super Action models, and were known as "Elimona". They remained basically the same from then up to the S99X series. DAVE