It doesn't really matter if you're comfortable hard modding. 10.4, 10.5 and 10.6 all use the same native_firm as 10.2. This enables us to modify our native_firm 10.4 and above to a 10.2 native_firm. Thus giving the user the ability to downgrade using sysupdater. Nintendo will have already mass produced this console, so if they release a newer firmware revision. It won't be pre-installed on this console.
To answer your question though, I don't think anyone will be able to confirm the actual firmware revision until we someone has it and is able to post the SKU.