No, you need to know that. I think they assume that you need to know the items being bought in order to know how to handle their purchase.
However, in reality, you can know how to handle the items being bought without knowing everything that's available. As an example, I've written a few apps that allow you to purchase downloadable content delivered via web services running on a server. New items you can purchase and download might be added after the app has shipped and I didn't want to have to submit an App Store update (and wait 7 days) every time that happened, since all purchased content is handed in the same way. So, I wrote a web service to return the available product identifiers to the app and passed those to storekit. All I need to do when I want to add new items is add more IAP products in iTunes Connect, update the server database to indicate what's available and put a zip of the content on the server. The app itself is stupid about what's available, but it knows how to download and use whatever items that are available, because they're all handled the same way.
Anyway, the answer to your question is "no."