I believe they are calf. They have a more oily/waxy texture than normal calf and almost feel a touch moist. They are very soft and comfortable right out of the box. If anything, they seem to fit a touch more snug than regular calf which is fine with me since the P2 is already on the slightly looser side of the F last which fits me best. The color there is fairly close to in-real-life. The derbies I have I darkened a shade last night and it took the polish really well. I'll try and post a comparison shot showing the two CXL side by side.
Here's a photo of the original CXL color (boot) and darkened (derby). The derby was originally a touch lighter than the boot which you can tell at the top of the tongue of the derby where I didn't touch it. I darkened it with just one layer of dark brown cream and one layer of dark brown wax. I'll likely darken it more as it really took the polish well.