Layout of a Morrison Leukoscope lens?

[Mark Sawyer]

I recently purchased a No. 1 Morrison Leukoscope lens. It arrived hazy and dirty, but cleaned up quite nicely, with no flaws to the glass at all. I kept careful track of each cell as I disassembled it for cleaning, but the layout of the rear cell seemed a bit unusual. Does anyone know of the layout/order of elements in the Leukoscope? Or if someone has a Leukoscope, is the rear-most glass surface almost planar?

Maybe I'm just being paranoid, but I've run into a number of mis-assembled old lenses through the years, and want to get this one right!