When overhauling the transmission, replacing as many of the wear and damage prone components as possible will simplify the assembly process required to set up the gearbox correctly. Some of the collars and washers, in particular, act as spacer shims and need to be perfect with zero wear or damage.
This will improve the change quality and help achieve a smooth, quiet running transmission assembly.
You may wish to consider these other transmission components that could make the difference between 100% perfection - or something less: