It's common for the fences to be removed last minute, unless they somehow prevent access to your property including parking, you will have to live with some element of temporary fencing until the the development is complete and common areas finished off.
As above, slow down and don't book anything until you actually have the keys. Late surprises are less common on new builds but they do crop up from time to time. A few extra days without a floor won't be significant in the long term, and might even give you more time in the space to figure out what you really want.