Peter, what you suggest is of course possible although I agree with Tony's point as well.  If you read what is said on the linked page, there is specific statement that it is a "true color Autochrome Plate" and he goes on to discuss the very high cost of that technology in that era.  I have no reason to doubt that the individual that posted it knows whereof he speaks.  Here are some links about the development of the Autochrome color process by the Lumière brothers in the first years of the 20th Century and some examples of its use from National Geographic's archives, not surprisingly an "early adopter".
https://en.wikipedia.org/wiki/Autochrome_Lumière
https://www.sharkandpalm.com/news/the-oldest-color-photos-discovered-in-the-national-geographic-archives

 I would just add that the Shackleton expedition in the Antarctic in 1914 included a photographer, Frank Hurley, who was taking color images using the Paget process, when actually in the Antarctic. Luckily they survived the harrowing later stages of that expedition.