And as was brought up in another question recently, some buildings might require a builder to (re)place in your city, and you will need to have the available Culture and/or Population to place the building. Also, be aware that Wonders that provide Pop based on a percentage of Working Pop or Culture based on a percentage of Required Culture provide their benefit after new buildings have been placed' you might be restoring exactly the same buildings of exactly the same levels as you previously had and not be able to return all the buildings from inventory.