It is just one book..just like the old days.
The coupons are all just stapled together and the last ones could easily be removed and left behind for safe keeping.

What I was trying to figure out was if there was a reason that I might need the complete ticket booklet for any reason.

I have just figured out that if for some reason I needed/wanted to change the ticket in a way that required re-ticketing, I would need to turn in the old ticket.
Two earlier calls to UA got me two different answers. That is the reason I posted the question on FT. Much more likely to get a accurate answer.