I think your wording is confusing. Are you talking about booking seats (often used as a colloquial shorthand for getting a ticket which entitles you to some seat on the airplane) or reserving seat assignments (ie getting assigned particular seats, like 23A and 23B)? The term "booking" is rarely used to refer to getting seat assignments, I think; hence the confusion.

I wouldn't worry much about seat assignments 11 months out. Seat assignments are never guaranteed and can always change. Certainly worth getting seat assignments if you can, but not worth making a purchasing decision based on it. As others have noted, award availability allowing you to book a ticket will almost certainly be more of a hurdle than getting seat assignments. Seat assignments are also much easier to sort out at a later date than getting a ticket on the same plane.