Is this from when then hammer is fully forward after dry firing? If so it is most likely the sound of the hammer and catch resetting.The click happens after applying a few pounds f pressure, it's not parts rubbing together, definitely a slight clicking sound.
To best describe it. When the hammer is decocked, when i put like a pound of pressure, even before the hammer starts going back, there is a clicking sound. Then if I let go of the trigger, and the hammer is still down, it doesnt do it anymore.Don't take our word for it. Pull the slide and watch the parts. Only clicks from the completely down (dry fired) position. Where the hammer will never be in normal operation.
Take this for what it's worth. A long time ago, when I first got into buying guns, I used to look over the gun like it was something crafted out of gold and diamonds. I also used to take every effort I could to analyze the smallest detail when shooting and cleaning the gun. I got over this when I realized I was spending more time stressing over these things than enjoying the pistol. After reading the question about the scratch, and now this; I think you might be in that place.
IMHO, you will find so much more pleasure in your things if you don't spend all the time agonizing about the small imperfections, but instead focusing on how well they do the thing they were made to do. There are slight clicks in my triggers too, but they either go away with time or I just don't notice them.
There are a lot of things happening when the trigger is pulled, as long as the pistol works I would not worry. How does the pistol shoot?