I believe she says she had two swords but gave one to Penny
Yes, but they both have the "double scabbard" set up. You might have one double if you normally carried two, but you'd also likely get a single for your friend is you were loaning one out. I know how expensive swords and scabbards are - you don't go around throwing good money away unnecessarily, especially on something as frivolous as a double scabbard set up would be.
That money could be used for another nice dagger or something. 
Honestly, I've never actually seen a double scabbard set-up in reality. If you're carrying two swords, they'll usually have their own separate suspensions, with one layering over the other, and they also will not usually be for weapons of the same length (Chinese butterfly swords being an exception, but they are designed to go into a single scabbard). I know this is all just fantasy, but some of the unrealistic stuff you see doesn't exist because it just really isn't practical. And when it comes to combat and self-defense, practical and easily accessed are paramount to a good outcome.
In fantasy, I don't mind if you magic the shit out of things and
deus ex machina all day long, but don't get impractical with your reality based weaponry.
