Personally, I tend to learn things new things a little slowly, so I would have found it helpful to audit an organic lecture before I actually took the course. There is no substitute for familiarity. I just tend to not get the point that is being made until, say, a week after the exam. After the exam though, I usually don't forget what I learned. That might just be me though.
I tried to audit a couple of courses in college, but it never worked out because I always made some excuse not to go to the lecture. To audit a class effectively you have to really commit to doing it and you have to treat it like a class you are taking for credit. You'll probably get lost in organic lectures if you don't supplement what you are learning with some problems and reading.
That said, I would say that auditing the course could help tremendously when you do take the course for credit. Those of us around the forums would be happy to fill in the blanks that you might encounter. In reality there probably isn't all that much that you need to know from gen. chem. to follow the concepts of organic.