Here is my #3 back
I hope this helps, from the NSSC
NSSC 1 - 10 has a fine cross-wire mesh that can best be seen by holding
the stamp edgewise towards a strong light. This mesh is difficult to see on the 3d NSSC 3 and 4. The colour of the 3d is yellow green and most copies show a strong offset of the design on the back.
Crossed Wire Mesh on Left,