@Aleksandar Micev has created subreddits in the past, he can answer this question better than I can.
In my opinion it depends on the goal of the sub reddit, if you plan to promote your product in the subreddit in any kind of way, you should clearly state that it is the official Reddit forum of your business.
You can go with your second option but you have to be really careful and subtle when posting about your company and product.