This article is more pessimistic about porting over new apps. It basiscally says that if you wanted to use the .apk (or the source code that makes up an app) to install an app from an old device, it would be impossible unless you rooted the old phone. I don't know how tech savvy you are, but rooting your phone might void the warranty, which usually isn't a good thing.
That being said, you're probably going to be okay trying the first method.