Goofs section is wrong !
In the goofs section its states as the last factual error : -
Factual errors: If you look carefully, it's easy to see that the four keys requiring all of this work are just two pairs of duplicate keys - and, to any locksmith, it's obvious that the keys shown are for lever locks. Not only are they pretty easy to pick (even back then), the extensive waxing procedure shown to duplicate the keys wouldn't have been neccesary - one side of the key is all that's needed for a copy.
That may be the case, but in the original robbery in 1855, Pierce and Agar did actually make an impression of the said key twice, so even though this might seem to be a dumb thing to do, this fact cannot be regarded as a factual error, as it really did happen in real life !!