Doesn't appear to be your actual Plein Air. More of a do it yourself roofless R4. Very difficult to tell from the photos whether it is a good one or not - a visit before buying would definately be a good idea.
The boot lid seems to have become part of the shell on this one. If I were visiting I'd check that the effect hasn't been achieved by way of body filler. Bit of welding first would probably be acceptable and it would get rid of that annoying tailgate squeak.