Just to clarify the production of the Convertible D, it was produced only for one model year: 1959. It was actually produced in two calendar years: from August, 1958 through August, 1959, and possibly into September, 1959.
Some owners will note that their Convertible Ds were first sold and then registered by a department of motor vehicles, a secretary of state, or some other governing unit in late 1958, 1959 and 1960. This is due to when their D was actually sold in the country and province and/or state in which the car was delivered. For example, although a Convertible D will be a 1959 model, it might be licensed as a 1958 Conv. D, since it was sold and registered in late 1958. Sometimes a car might be sold much later than when the factory built and then delivered the car to an original dealer. Also, on occasion, a car was not sold at the original dealership, but sent to another dealership to sell. If the car didn't sell in 1959, it sold in early 1960 and then was registered as a 1960 Conv. D. Some reasons were to lower the inventory of the original dealership and to sell cars more quickly in locations where these cars were more accepted, such as in warmer climates.
Please keep in mind that 356s were hand-built cars. Convertible Ds were not always produced in exact chassis number order at Drauz, the coachbuilder. They frequently arrived at the Porsche factory out of sequence. Also, Porsche may not have finished them in any particular order, especially if an inspector found a flaw that needed correcting or they needed to add a special ordered option or item.
For more interesting facts and information about the Convertible D model, select a link at the left under "D Details".
*According to Steve Heinrichs, on 356TALK, Jan. 15, 2006, upon additional research after publishing the book Porsche Speedster TYP 540: Quintessential Sports Car, 2004.