I'm not really sure. It's possibly Jay is, as he picked up some of Doug's supplies and plans..
Alternatively, these would not be too difficult to fabricate yourself with some bar stock and a cut-off bit for a rotary tool.. (And patience.) You could use the Energy Suspension bracket as a template for the backer plate.. but do note that you have to trim a corner on each of the rear plates, as well as the bushing bracket, as shown in the photos..
I do have Doug's kit on my car, and it's fantastic. This is a mod that's worth doing. (Particularly if you've already broken one of the stock brackets, as I did.)