Pretty sure that's colostrum. But I wouldn't be worried about that, or that it was only one side. Some women don't leak at all pre-baby :)
Yup, that's what it is. Mine haven't been leaking on their own but if I squeeze my nipples, drops come out. They've been doing this for the last month. I squeeze them a few times a day just so that it doesn't build up and leak on their own. My right nipple has had more colostrum than my left for the last few days.