How do I get the Entry object from my pre_render function

I'm hooking in to my form with gfrom_pre_render_1 - in this hook, I'm changing a dropdown to dynamic options populated from a custom post type. This works perfect. Yay.

However, now my problem is, if the form is submitted with errors, the form re-renders with non of the selected dropdowns.

I'd like to know if there's a static method or some way of getting the Entry object from my pre_render function so I can check and mark the selected options, selected again on submission error.

Also, I'm getting a Missing argument error with the gform_after_submission hook. Using the latest release: 1.6.4.3

add_action("gform_after_submission_4", "book_after_submission");
function book_after_submission($entry,$form) {
	var_dump($entry);
	var_dump($form); die();
}

Thanks Alex. Inspecting the $_POST variable did the trick!