I think the problem with such a statement is that the one experiencing the perception of such symbols never actually has to concretize them into art or mythology. Perhaps the culture on the whole wouldn't have the ability to replicate the symbols (or understand them) anyway. For example, let's say 1000 years ago, an Amazonian shaman had drunk ayahuasca and experienced glorious Egyptian visions, perceiving the most pertinent of their religious symbols. Obviously they would be completely otherwise unaware of the culture and said symbols because they don't share our lofty contemporary perspective in the West of photographs, videos, textbooks, archaeology records and other Egyptological claims of the culture. Perhaps scant parts of the vision may end up completely transfigured into their already existing Shipibo visual-language, but it needn't be obvious in any shape or form that they experienced such a vision at all.
To take your specific example of the old man with the small dog, the limp, the hat and the cane, it could be theoretically possible that such symbols appear to contemporary budding psychonauts in a DMT vision for example; however, it might seem like such a silly, bizarre aspect of the vision, that it is completely written off. They write no reports of it; they create no artwork of it; their perceptions don't become shared and even if they do, it may likely not end up surviving 1000 years for future archaeologists to digest and say "well those psychonauts of that era certainly weren't aware of such symbols because they never appear in the record or in the culture and significant. The main point is that we can't presuppose the perceptions of other cultures because limited understanding and limited artistic abilities and the limitations of language all play into this big hodgepodge.
I will point again to the Ganesha example in which we have numerous members on this site who have perceived Ganesha and whom were completely unaware of her and/or her teachings, and yet they experienced her in a contextually significant way (as the Initiator or Remover of Obstacles). Now, even though they may have taken the time to write some small bit about her and even if she has had a profound impact on their lives, it doesn't necessarily have to be translated to the culture in which they experienced her. There needn't be new elephant cults or a Western veneration of the elephant as sacred or anything obvious in which a future culture can look back and know that it wasn't just the Hindus who perceived Ganesha directly, but a whole slew of DMT users whom were not familiar with Ganesha either.