You may want to when you read this on The Rejecter:

Have you received queries or submissions that have mentioned NaNoWriMo? If so, have any of these submissions been accepted for representation, or at least passed up the ladder?

If the agent would recognize it, they would actually probably pass on it, for a number of reasons. First of all, 50k is just too low unless it's YA or a children's book. Second, only the fastest writers can write a quality full-length novel in a month - most authors need a year. The speed at which it was written is an indication against it. Third, if they wrote it in November and they submit it in December or January, they obviously haven't done the heavy polishing any manuscript needs before it's ready to be submitted.

More here.