[Momquist]

The url can be found via the archive's API, and you can specify a timestamp.

http://archive.org/wayback/available?url=http://yorktownhist...

It returns a json with, notably, the closest archived page given the timestamp.

https://archive.org/help/wayback_api.php

[degenerate]

That's way more fantastic than I thought their API would be! Thanks. Hope OP sees it.