Get Order of Meta Box in a Page/Post

It’s not that hard: There’s a user Meta entry for that.

You can not only retrieve the order, but also which ones are hidden (just to get one step further).

# Meta Box Order
$meta_box_order = get_user_meta( 
     wp_get_current_user()->ID
    ,sprintf( 'meta-box-order_%s', get_post_type() )
    ,true
);

# Hidden Meta Box
$meta_box_hidden = get_user_meta( 
     wp_get_current_user()->ID
    ,sprintf( 'metaboxhidden_%s', get_post_type() )
    ,true
);