How to get line item type from the add to cart form

I would like to show a custom text on the Add to cart form submit button.

Here is documentation https://drupalcommerce.org/discussions/613/how-change-add-cart-button-bu...
How to change the submit button text based on product type:

<?php
function mymodule_form_commerce_cart_add_to_cart_form_alter(&$form, &$form_state) {
  $line_item = $form_state['line_item'];
  $product = commerce_product_load($line_item->commerce_product[LANGUAGE_NONE][0]['product_id']);
  if ($product->type == 'gift_product') {
    $form['submit'] = array(
      '#type' => 'submit',
      '#value' => t('Give'),
    );
  }
}
?>

How to change the form submit text in general:

<?php
function MYMODULE_form_alter(&$form, &$form_state, $form_id) { 
  if (strpos($form_id, 'commerce_cart_add_to_cart_form') !== FALSE) {
    $form['submit'] = array(
      '#type' => 'submit',
      '#value' => t('Buy now'),
    );
  }
}
?>

How to do that based on the line item type, on D7, latest stable Commerce?

Will this do the work? (not a developer):

<?php
function mymodule_form_commerce_cart_add_to_cart_form_alter(&$form, &$form_state) {
  $line_item = $form_state['line_item'];
  if ($line_item->type == 'gift') {
    $form['submit'] = array(
      '#type' => 'submit',
      '#value' => t('Give'),
    );
  }
  elseif ($line_item->type == 'contribution') {
    $form['submit'] = array(
      '#type' => 'submit',
      '#value' => t('Contribute'),
    );
  }
}
?>

My usecase:
I have a view with 2 add to cart forms for each product listed (a giftlist).

• One is using the standard line item type,
• the other is using a custom one, to let the user input a value (a contribution amount)

I would like a "Give" button and a "Contribute" button.

PS: I could not post a comment on the linked page because the site gives me error when I try to login
PPS: I image this is really simple, but I couldn't find any documentation since custom line items are contrib

Thanks!