Hi,
Yes, b is the same as the PCB layout. Or rather, yes and no - if the PCB shows the underside of the board where the soldered pins go, then yes; if the PCB shows the top, where the trimpot body will be, then no - the screw/dial will be on the other side to the PCB footprint when placed. In your mind's eye, turn the drawing 90º clockwise, then rotate the trimpot 180º on the horizontal plane and you'll see. 90º anti-clockwise will have the screw on the right side of the PCB layout but it'll be at the upper, not lower half.
It seems to be for the side screw version pot, rather than the version with the screw/dial on the top.