Iris Rev. 3 and 4 PCBs have the same exact USB-C and TRRS port positioning, so they also use the same case design.
Most of the files are designed for the the left half, so to get the right half, just mirror the file
For the top shell files in this folder, the screws are threaded in from underneath, instead of from the top for the files in the top level folder. The main benefit of this style is that the screws are not visible from the top.
The depth of the screw hole is about 5mm, so the length of the M2 screw you need with depend on the thickness of the plates and mid layer you use. Make sure the screw threads into the top shell for at least 3mm. For example, if you are using 1.5mm switch/bottom plates and 12mm middle layer, then you would need to use 18mm screws at the minimum (3 + 1.5 + 12 + 1.5 = 18).
Since some of the middle layer files have port cutouts, the version that needs to be used is dependent on the the switch plate thickness. For FR4 plates, use the files designated for 1.5mm plates. For 3mm acrylic plates, use the files for 3mm plates.