I just got a new job and I had a gap for one month and I indicated I was unemployed just to complete the form. But I forgot about a 2 week job that quit because it was not my job path or something I wanted to continue with. My question is will that raise a red flag or should I tell them. Is this something to worry about or just let it go and wait if they ask.
Well, there's no harm in being truthful. There's nothing you wanted to hide, you simply missed to supply the info.
Just send an addendum mentioning your honest mistake. I don't see it will make a huge difference, but then again, you'll be fair from your side. If they are not going to be bothered in future, they are not going to be bothered now by this.
Think of the other side: If this comes up in the background verification, you have to anyways disclose the information, so why not do it now itself?