For anyone still looking for way to retrieve the last4 numbers of the credit card so that they are available for the receipt etc, here is the solution:
After Larry's code:
$charge =\Stripe\charge::create(array(
"amount" => $order_total,
"currency" => "usd",
"source" = > $token,
"description" => $_SESSION['email'], ));
place the following line of code:
$last4 = $charge->source->last4;
then update the order query to replace the previous number from $cc_last_four.