If it's basecoat you will need to clear it. If it's direct gloss you wont need to.
For the record Concept Paints make decent paint. They have their own line of products...
http://www.conceptpaints.com.au/ would be the place to go to check up. Just because if you get the wrong paint to paint a car with and you dont match the primer/basecoat/topcoat/clearcoat with the right hardener and thinners, the results can be tragic, which would be no good. From a quick check i cant see a metallic topcoat so i would think it is basecoat. But best to check.
Good luck with the sale, i hope ive helped