The grip pattern has borders.
The borders were not very deep and they are the first thing to wear.
There should be a border all the way around EXCEPT at the rear part in the crotch of the grip.
Seeing a border here is a dead givaway that the pattern was recut by someone who doesn't know Parkers well enough.
Example:
image.jpg
Gunline makes a concave cutter. But it has to be used in conjunction with other line cutters. I like to use a 26 line per inch triple spacer. Then run the concave cutter down the center line.
DH checkering can vary from 18 lines per inch to 24 lines per inch. Depends on the gun.