No you should be able to get the value back by unserializing the cookie.
When you do the seriliazation you should also urlencode for the best results. Then you want to urldecode and unserialize.
To write the cookie:
$cookie = serialize($cookievalue);
$cookie = urlencode($cookie);
To get cookie:
$cookievalue = urldecode($cookie);
$cookievalue = unserialize($cookievalue);
That should work.
