add_filter( 'wcfm_per_product_shipping_fields', function( $fields, $shipping_fields, $product_id ) {
    if( isset( $fields['_per_product_shipping_rules'] ) && isset( $fields['_per_product_shipping_rules']['options'] ) ) {
        if( isset( $fields['_per_product_shipping_rules']['options']['state'] ) ) unset( $fields['_per_product_shipping_rules']['options']['state'] );
        if( isset( $fields['_per_product_shipping_rules']['options']['postcode'] ) ) unset( $fields['_per_product_shipping_rules']['options']['postcode'] );
    }
    return $fields;
}, 999, 3 );