Speedy 723, You're confusing oranges and apples.The speedster is a different fruit than the cabriolet.
The cabriolet was a comfortable all weather top of the line item: Roll up windows, body integrated windshield frame, radio, cushy seats, thick padded top that didn't flap in the wind...whereas the speedster was the bare bones item whos production ended in 1958: Door curtains instead of windows, low slung uncomfortable one piece seats, no provision for radio, flimsy top, separate windshield frame, and a 'turtle' rear engine deck...a much sexier piece of fruit than the cabriolet!!!
For one year only, 1959, the sexy turtle back 356A speedster received a body integrated windshield frame to acommodate roll up windows, and was designated "Convertible D" (for Drauz)
In 1960 with the revamped 356B styling this became a Porsche Roadster...roll up windows but still bare bones...and still sexy!!
So the roll up window replicas of the 356A that are referred to as 'roadsters' are really replicating the '59 Convertible D
But what the hell, a rose by any other name...