Not always. Barnes and Noble's manga stock changes frequently, and the presence of fan service manga isn't guaranteed. You might find some popular titles, but it's hit or miss.
The One Piece manga is not in color. It's presented in black and white, which allows for greater focus on the linework and details of the illustrations. Colorized versions might exist in some limited cases, but the majority of the manga is black and white.
The One Piece manga has gone on hiatus in the past. This could be for various reasons like ensuring the quality of the story or taking a break to recharge creativity.