The 1977 camera mentioned halfway through the video might have been the first consumer camera that superimposes the date, but it was common for aerial photos to have metadata like that added to the margins, like https://map.geoportail.lu/aerial/1977_30000/pdfs/0181.pdf
There are also digital cameras that "print" the date onto the pictures, I saw someone had this feature turned on and I thought explaining EXIF to them might be too difficult.
I know all about EXIF, but whenever I'm taking pictures that may end up being used in legal disputes[1], I deliberately turn on this feature. THis is for multiple reasons: EXIF data can be easily faked, everyone knows how watermarked timestamps work, and the baked-in timestamp will persevere across all subsequent media conversions (jpeg-to-bmp, emails, uploads, print-to-paper,picture-of-a-picture, PDFs)
1. e.g. pictures after a traffic accident, received goods in poor condition, or state of property at start of a lease.