Mp3 -> wav ->?

A friend of mine gave me an audio cd, and I suspect that the data on it may at one time have been in mp3 form.

I’m a big fan of lossless codecs, but I would hate to think that I’m making these 20mb audio files when the originals were 3mb. Is there a way to tell for sure wether a audio file has been, at some point, compressed? (question 1)

On the same idea, is it possible to have a wav re-encoded to it’s original mp3 form without discarding more of the sound? (question 2)

Question 1: Spectral analysis of the file, either with Audacity or Adobe Audition.
Question 2: Nope, more quality will be lost!