I'm not sure what you're saying. I'm not expecting Storable to guarantee anything other than that it'll serialize hashes by sorted key order, which is what setting $Storable::canonical to true is supposed to do. From the Storable manpage:

If you set $Storable::canonical to some TRUE value, Storable will store hashes with the elements sorted by their key. This allows you to compare data structures by comparing their frozen representations (or even the compressed frozen representations), which can be useful for creating lookup tables for complicated queries.