A large number of the stones at Tiahuanaco - including Pumapunku - still have scars from being dragged to the site.
The walls at Sacsayhuaman are Yucay limestone, not andesite.
The Spanish observed and wrote about the Incan stonemasonry methods. They didn't witness the construction of Sacsayhuaman, though. But we do know the walls there were built by the Inca - even though the earliest construction at the site is not Incan.