I don't know who 'they' are, but 'they' made an error or two
The Aussie model Sunny [B310] was discontinued in 1981, so finding a mid 80's example will be difficult.

The Aussie spec B310 Sunny did NOT come with a five speed.
According to one of our members, some five speed equiped coupes were sold somewhere up north [Queensland?] right at the end of the model run & i suspect that these might have been Japspec cars that were landed either accidentally, so rebadged & sole to avoid returning them, or possibly on purpose to simply sell off the last cars.

Either way, it is believed that a small number were sold. A very small number.

The five speed is not covered in the latest edition of the factory workshop manual for the Aussie spec Sunny.