The installers for those two components are independent to each other.
You could have an IM Server running with an IME that does not have a Provisioning Server if there is no need to manage endpoint accounts.
The Provisioning Server used to be a stand alone product called CA Admin prior to it becoming a component of Identity Manager, but having a Provisioning Server without an IM Server however is no longer how the solution is designed and there are times where you must use the IM User Console to gain access to things.