From what I remember, it seems railroads used old ties to makes chocks, is that correct?
Generally no, as the old crested ties would have been pretty difficult to cut/saw, plus would be all split, i.e. if they were still good enough for ties, they wouldn't have been removed.
I suspect it would also be prototypical to use any lumber lying around that was big enough. Thx.
Not really. The wood selected for heavy duty chocks was/is generally heavy hard wood, like oak blocking.