"The restoration of the Hieroglyphic Stairway was directed by Stromsvik during the late 1930s and early 1940s. At first, only the steps that had been found in order were restored, with the bottom-most steps merely consolidated in situ, and the other (slumped) steps placed about two-thirds of the way up the stairway. This proved to be an unsatisfactory solution, because it meant that hundreds of blocks would be left on the surface of the site, to collect moss, deteriorate further, and be subjected to the whims of visitors to the site.
Stromsvik therefore subsequently returned all the other known glyph blocks and human figure fragments back to the stairway. In doing so, the glyph blocks which made up deciphered dates in the Long Count were placed in sequence, while the rest were placed in a more or less haphazard way, to fill in the remaining spaces. Given their knowledge at the time and their concern for the conservation and restoration--or 'repair', as they called it--this was the most responsible course of action available to them."
William L. Fash, Scribes, Warriors and Kings: The City of Copán and the Ancient Maya, p. 140-41