P3's and P4's are all plate proofs, so they would have the registration lines. I would think centering the vignette was a big problem for them, this set the first time they had to do that.
The P1 and P2 being die proofs would not ever have the registration lines.
I am leaning toward this is a cut down P1, based on no lines and the margin sizes.
Here are the registration lines on the Atlanta's, you can see the second color lines easily, since it was from a plate.
