I don't know if it is that straight forward. I wouldn't recommend open sourcing your first round of code if it is the core of your business, but then again you should have copyright to your own code and if you are clever enough it gives you street cred when you try to sell the stuff. Competition is usually busy trying to figure out their own problems and if they copy from you, you can use it in your marketing and perhaps in future lawsuits. It's pretty rare that you've actually invented something really new and if you have I guess patenting would be to way to protect that.
If you want to drum up publicity I doubt going open source is going to do that in your prospective customers.