I doubt they were there too. They were just kids after all. There's no way Roger took then into the NW. We really don't even know the history of Shanks and Buggy anyway or how they came to join the Roger crew. They might have been orphans that Roger decided to "adopt" for all we know.
I say "adopt" because there have been many comparisons between Luffy and Roger in terms of personality. We all know how Luffy is. He see's someone he likes and flat out asks them to join the crew then and there without second thought. I would LOL if Roger was the same. "Hey you kids, I like your style. Wanna go on a little boat ride with me!"
