I'll add that the P-38 Commercial marked guns were made until 1995 before production finally ended, so not all later guns are all P1's.
Basically, the P1 was the P-38 made for the West German military who adopted it as the Pistole One, or P1.
The P-38 marked guns were made for German police and for commercial sales all over the world.
The two guns are essentially the same gun, similar to the commercial Colt Government Model and a Colt-made Model 1911 USGI issue gun.
Shoot 115 to 125 grain standard load ammo.
Using hot ammo, heavier bullets, or installing extra-power springs can crack or breaks slides and frames.
People figure they can shoot hotter ammo by installing stronger springs, not understanding that this makes the slide slam SHUT with much greater force.
I've seen P1 and P-38 pistols with cracks through the frame in the take-down lever hole from the slide slamming shut after extra-power springs were installed.
Again, to be clear, the P1/P-38 rear sight is NOT WINDAGE ADJUSTABLE.
I've seen guns seriously damaged after unknowing owners tried to beat the sight over.
All adjustments are made to the front sight. Higher or lower sights are available from Earl's Walther Repair.
Apparently there are rear sights that are or were available that have the notch shifted to one side or another to adjust for windage if the front sight isn't enough.
Note that the Walther has a "interesting" quirk: It ejects cases to the LEFT, not to the right.
Once in a while, just to keep your attention it'll throw one straight at your head.