How to access a freeform field object's properties from an event
To answer my own question, this is what I found.
The answer is to use get... methods.

craft()-&gt;on(
    "freeform_submissions.onBeforeSave",
    function (Event $event) {
        $submission = $event-&gt;params["model"];
        $field_item = $submission-&gt;fieldMetadata['field_handle'];
        $field_value = $field_item-&gt;getValue();

    }
);


The $field_item-&gt;getValue() can be $field_item-&gt;getId() or $field_item-&gt;getHandle() and so on.

The properties listed here: https://solspace.com/craft/freeform/docs/field/ can be used by turning the property into a method and prepending get.