Quoting Ken Arromdee <arromdee@gmx.com>:
On Thu, 24 Jan 2019, Greg Newby wrote:
It is possible by comparing the full 2009 edition with a printed copy from 1923. It's not impossible, it is just extra work.
In this type of situation, it might be easier to obtain a 1923 printed publication and scan it.
If you have to have the original in order to prove that it's okay to scan the reprint, that essentially means that reprints are useless as a source of scans at all (barring edge cases like originals that you don't have permission to scan but do have permission to read).
That is right, but a lot of reprints are facsimiles, and in this case (if it is mentioned, or very clear from the appearance), no need to access the original. I've got several clearances based on this. Jeroen