A good cowl installation (regardless of what fastening method is used) requires a net fit of the cowl halves to each other and to the fuselage.
The sign of a great installation is that with the top cowl sitting in place on the bottom half, you can't tell if the pins are installed yet......
If the installation was poorly done and force/pressure needs to be used to get the cowl halves into proper position and install the fasteners, the entire installation will be plagued with problems (broken rivets, hinge loops, cam-lock studs, etc.).
This often occurs because of excess trimming which makes the builder pull things into alignment so that the gap doesn't look bad. After just a couple of instances of doing this, the cowl will be under a strain that will make removal and installation difficult, and will influence the overall longevity of the installation. Strain+vibration=destruction (over time).