Reverse post order in a specific category

sc_post_order_reverse.php

// Runs before the posts are fetched
add_action( 'pre_get_posts' , 'specific_category_reverse_post_order' );

function specific_category_reverse_post_order( $query ) {
  // Alter only the primary query and only if we are in post lists context
  // How to use is_category -> http://codex.wordpress.org/Function_Reference/is_category 
  if( ! ( $query->is_main_query() && is_category('3') ) )
    return;
  
  $query->set( 'order' , 'ASC' );

  // reverse the pagination links
  add_filter( 'tc_list_nav_previous_text', 'previous_text' );
  add_filter( 'tc_list_nav_next_text', 'previous_text' );

  // add css to swap the pagination buttons
  add_filter( 'tc_user_options_style', 'sc_reverse_post_order_inline_css' );
}

function previous_text(){
  $current_filter = current_filter();
  $filter_labels = array(
    //filter => label
   'tc_list_nav_previous_text' => __( '<span class="meta-nav">&larr;</span> Older posts' , 'customizr-child' ),
   'tc_list_nav_next_text' => __( 'Newer posts <span class="meta-nav">&rarr;</span>' , 'customizr-child' )
  );
  return $filter_labels[$current_filter];
}

function sc_reverse_post_order_inline_css( $_css ){
  return sprintf("%s\n%s",
      $_css,
      '
        #nav-below .nav-previous { float: right;}
        #nav-below .nav-next { float: left;}
      '
  );
}