Hello,
It is not possible for guest to have wishlist. The simple reason is that, because they can't log-in, if they close their browser or their session is lost, the wishlist will be lost too.
You will find a lot of thread talking about the exact same subject.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.