It generally won't come with the back housing. Seperate part (unfortunately) .. think of those AE86 kids overseas who rebuild their motor and have no need to buy the rear part of the housing sorta makes sense. But you can order everything you need in one hit, see below
16110-16010 - JUST the front half of the waterpump
16100-19095 - the entire waterpump assembly, including thermostat housing etc (but no thermostat)