I think most new guns (as well as most mechanical devices) can Benefit from hand fitting and liberal use of Prussian Blue dye. That is best done before use, Parts with a minor misfit unseen by your eye easily produce poor wear patterns that are difficult to remedy. That is the difference between a hand fit gun to a factory fit one. That is the primary work done by high end pistolsmiths like King. They can spend hours applying dye to contact surfaces assembling and disassembling doing fine polish to high spots producing a perfect even fit. Even companies that build custom rifles.....many on Remington 700 actions......spend a lot of time squaring and fitting everything befor starting the build. That is how they improve the smoothness and consistent accuracy on a gun that is already accurate from the factory. The labor costs can seem like a lot.....the work requires a lot of time......but in the long run worth it.