Interesting kit, and will be a great set of stoppers. Looking at the AP calipers I don't think they are not the ones that AP use on the TT kit, which has only been out for a couple of years, so it may be a custom brake set up, with calipers off another car or supplied direct from AP.
They were doing that a while ago, they would supply the basic bits but it was up to you to make it all fit. My mate did one for his race Morgan once, it took a while to sort bells and brackets but an amazing set of stoppers. This looks like someone has done all the hard work for you.
Its a good price it will interesting to see what it goes for.