I've never been a fan of naming user stories. Stories should generally be short enough that naming them should not be necessary.
Yes, novels and movies get names. But we don't name the sentences in a novel. Since I still haven't been to see The Great Gatsby movie I started re-reading the novel recently so it's on my mind. Imagine Fitzgerald and his editor (Maxwell Perkins) discussing the book and Fitzgerald saying of the opening, "This is the 
'remembering my father giving me advice' sentence. And this is the 'father gives that advice sentence.' And, Maxwell, what do you think of 'fundamental decencies' sentence?"
If I picture Fitzgerald and Perkins discussing a final draft of the sentence, I'm much more likely to picture Fitzgerald saying, "Maxwell, What do you think of this sentence?" and then pointing to it.
And that's just how I interact with user stories. I call them 'this' and I point to them. Or I simply read them aloud to the person I'm talking to--in the same way Fitzgerald might have read a sentence to Perkins in order to discuss it.
So, my advice is not to name your user stories. And definitely don't number them. That gets way too confusing. In User Stories Applied I advised against numbering stories, especially with numbers like 15, 15.1, and 15.1.1 to indicate relationships. Maybe a tool does that for you and you can ignore the numbers until the rare occasion on which you need the number. But I sure wouldn't number stories on cards manually. I have encountered one team though that used a Bates stamp to number their cards. (Bates Numbering refers to using a type of stamp that automatically increments each time the stamp is depressed. It's very common in the legal field and that's where I encountered the one team who did it.)
For themes, which are groups of related user stories, I will usually put a separate index card on top of the theme and label it. I tend to use one- to three-word labels like "Reporting" or "Loan Processing" or "Shopping Cart Improvements" or "Performance" and so on. Within the theme, though, individual stories are not named.
Now, back to reading The Great Gatsby, quite happy that Fitzgerald just tells the story and didn't name each sentence.
