wcraq_add_cart_item_data.php

<?php
/**
 * Add cart item data.
 *
 * @param Array 		$cart_item_data Cart item meta data.
 * @param Integer   $product_id     Product ID.
 * @param Boolean  	$variation_id   Variation ID.
 *
 * @return Array
 */
function wcraq_add_cart_item_data( $cart_item_data, $product_id, $variation_id, $quantity=0 ) {

	$product = wc_get_product( $product_id );

	if( wcraq_is_product_quotable( $product ) ) {
		$cart_item_data['wcraq_is_quotable'] = true;
	}

	return $cart_item_data;

}
add_filter( 'woocommerce_add_cart_item_data', 'wcraq_add_cart_item_data', 10, 4 );