They are in dovetails, right?
Do you have a micrometer or micrometer-caliper?
If you do, measure the heights of both front sights. Write each figure down.
(You measure sight height, in this case, by measuring from the bottom of the front sight's dovetail to the top of the sight blade.)
Now measure the heights of the rear sights, and write them down too.
(Measure from the bottom of the dovetail cut to the top of the rear-sight blade. I assume that the adjustable-sight gun is zeroed.)
What we're hoping to find is the same relationship between front and rear sight, gun for gun.
(The heights needn't be the same, but only that the relative heights should be the same.)
If the relative height you're seeking is the same, switch both sights from the fixed-sight gun to the other one. You should be pretty close to zero.
If the exact heights you've measured on one gun are the same as those on the other, you need switch only the rear sight.
Before removing any sight, make scratch-marks as index-marks on each sight and on the guns. In every case, get as close to the center of the top of the slide as you can. This will help you to come pretty close to a windage zero, but you'll probably need some further adjustment.
Use a plastic-face mallet, a solid plastic block against which to rest the gun's slide, and a drift punch made of aluminum, brass, or Nylon, to move the sights out of and into their dovetail cuts. Out from right to left; in from left to right...I think. (Better check. My memory's old.)
Does that help?