Actually, (an using my small legal expertise) if the letter was sent via standard mail, X, is where the signature is placed. OR, if the letter was sent via email, then it`s part of the edit done to it, to prevent us from seeing the name of the lawyer.
I want to help... So tell me, did the letter come from DLA Piper? (My father is a lawyer over there, and he has in past worked with Nintendo)
QUICK EDIT: Do yourselves a favor and remove the part of the article where it says that you're palying the ROMs
¶SB