Deathly Hallows : Was this Explained?

okay do you remember in the Chamber of Secrets when Harry used the sword. and Dumbledoor said that only a true Gryffindor can get like that. Well it sword was going to Neville and he was a true Gryffindor. SO I am guessing because the book doesn't explain that it doesn't matter if it is stolen of lost because it will come to you whenever a true gryffindor is in need. and as for who threw it down that could have been anyone... The Ghost. or someone else....