I actually don't think they did.
But so much time has passed since Book 2 was recorded that it's conceivable to me that the album could have been tinkered with and altered since P passed away.
But yeah, if the album is released as it was originally recorded, then I don't think we'll hear Havoc on it.
Books 1-3 were produced heavily by Alchemist, Knxwledge, Beat Butcher, Budgie (a lot of producers that Prodigy actually didn't have a big history of working with on the HNIC series.)
I think I have a preview of a couple songs off of Book 2 that I can try and dig up.