That was really good description of the statue and looking at it it really looks so old, as we know weather left its traces of stone, wind and water most probably made it more smooth and unrecognizable, still as you describe there are shape for hair and the ornament on the coat of that statue on back. The front of it more smooth but more features on back, may be it was at the wall or so so that back was protected from weather.
From looking at stone, it looks like sand stone, but sandstone may get destroyed more faster and if statue about 2000 years then it might be something stronger. Hopefully it will be there for more longer years for further generations :)