Add HTML element to popups with selected theme

I’m trying to add extra HTML to the popup template using the action hook popmake_popup_after_inner.

I have a few popups with different Popup Themes:
– Theme Default – ID: 133
– Theme with Flash – ID: 140

How can I add an extra HTML element only to popups with “Theme with Flash”?
My code below:

add_action('popmake_popup_after_inner', 'add_flash_element', 10);

function add_flash_element() {
    $flash_html = '';
    $flash_html = '<div class="popup-flash">' . __('Join', 'popup') . '</div>';

    echo $flash_html;
}