If you made a backup of everything then yes, you can restore from the backup. The update actually changes your product database entries so simply switching back to the previous version of WooCommerce wouldn't fix it, you have to also switch back to a previous version of the database too.
This topic goes over the details a bit more: http://www.woothemes.com/2013/02/preparing-your-website-for-woocommerce-2-0/
Regards,
Devin