Slight wear on the indicated places should not be perceptible as long as the teeth indicated by A are not worn out of shape.

What really affects how easy it is to select a gear are the "teeth" on the inside of the ring. You indicated the spaces between these teeth with B.

Run your finger over the inside of the synchromesh ring and feel if the teeth are sharp. If they aren't, the ring won't slide over the cone very easily (adhesive force from lubricant gets stronger when the teeth's tops become flat). That will require noticeably more force to shift gears, esp. between first-second and second-third.