No, there are default location fields for which you can insert your own field values. For example, the "State" field, you can enter in details specific to your own country (the US States are there by default, but can be replaced).. so that the customer can choose from a dropdown and you can obviously make that a required field as well.
You'll get a better idea of this by looking at the ClassiPress admin dashboard, specifically the
custom fields section.
The other thing to note is that this thread was started last year, and related to a much older version of ClassiPress. In the version 3.1 release (currently estimated for release at the end of November), there will be an advanced search which includes radius option.