My sink covers came with the trailer, same ones in the OP's pic.
At first it didn't have them, I showed the dealer where the 2012 Jayflight brochure said the sink covers came standard and I wanted them. At first the dealer said "No" they aren't included, but I pressed (especially since I had the brochure) so the dealer called Jayco and Jayco had them sent from the Mfg to my house directly.
Update: Just went back to look up the brochure, but the 2013 has been updated and no longer references the sink cover although the picture with sink covers is still included. Attached is a link for 2012 brochure that shows it. Page 9 under the "Customer Value Package" shows sink cover/cutting board. http://www.generalrv.com/common/brochures/mak5415.pdf