Featured image in CPT overview column

It looks like working. The post type slug is passed as a GET variable so if you want to add the code to specific post types, you can first grab the post type slug by:

if( isset($_GET['post_type']) ) {
    $post_type = $_GET['post_type'];

    if( in_array( $post_type, array('type1', 'type2', ...) ) ) {
        add_filter( 'manage_posts_columns' , 'jam_cpt_columns' );
        add_action( 'manage_posts_custom_column' , 'jam_cpt_columns_data', 10, 2 );
        add_filter( 'manage_pages_columns' , 'jam_cpt_columns' );
        add_action( 'manage_pages_custom_column' , 'jam_cpt_columns_data', 10, 2 );
    }
}

you can specify your desired post types in the array.