Yeah - But I won't say it's as easy as it looks.
I strip the patch box of the screws, lid & hinges.
I move the remaining patch box frame around on the side of the buttstock until it's positioned to my druthers.
I tape it in position, then sharpen a nail tip to make a scribe - holding the sharp tip against the side of the patch box frame and running the scribe around the patch box frame, holding the tip very tightly to the edge of the box where it rests atop the stock.
After that, it's a matter of skillfully inletting the wood within the scribed outline for the frame, then inletting an area deeper for the lid hinge, and finally drilling out the larger hole that holds caps/patches, under the lid.
I also drill pilot holes for the patch box screws & time the screw heads so the slot runs parallel to the C/L of the patch box. (front to rear)