Is there any significant flavour difference between dehydrated and sun-dried tomatoes?
Making dehydrated vs. sun dried tomatoes:

Dehydrated tomatoes appeared later than sun dried tomatoes, in part due to the added complexity in how they are made. For dehydrated tomatoes, the tomatoes are washed, then passed through long tunnels in which they are exposed to a current of warm air. It is a speedier alternative to the sun dried variety, and allows for greater variation in the product. Dehydrated tomatoes most commonly produced in Chile, Mexico, Morocco, California and in China. Dehydrated tomatoes have a moisture content below 7 percent, a less sharp taste and lighten slightly in color after 12 to 15 months of storage.
The making of sun dried tomatoes is different. Ripened tomatoes are first washed, halved and then usually put through a water bath containing sulfur dioxide. They are then put into drying trays in the sun for seven to ten days. Thereafter they are cut and packaged. The industrial market for sun dried tomatoes in North America is currently supplied by Chile, Turkey, Mexico, California, Spain, and Italy. Sun dried tomatoes typically have a 12 to 24 percent moisture content, are more robust in taste, and darken after expiration after nine to 12 months. Cool storage is recommended.

Source: Sundried vs Dehydrated tomatoes