Removing parts is not destroying it. The main reason they say you may not destroy it is. That if for example you committed a crime with it.
Then you go and damage the barrel. They can not test the barrel to see if it was your firearm used.
The barrel Slide and frame is the major parts to leave alone.
Screws, springs mags and grips are of no concern. Although needed to operate.
Can be added easily back.