Not for nothing, but we never had a slide projector growing up; I know absolutely nothing about slides. Is it even POSSIBLE to duplicate one only having the source slide itself?
It's probably not hard to scan in the image and then print it. You can likely do that on your home printer if it's of high enough quality, though if you're concerned about color differences from using home products, you'd want to take the job to a professional who can color match better. If you want "authenticity", you'll want to make sure you have the right material; you can get transparencies that are made from more than one material, and I don't know which one the original slides are.
If you were trying to "pass one off", then the other smell test would be the slide casings. You can get second-hand cardboard casings online, or you can 3d-print new ones. But those won't look like the original casings that these are in.
So... you could certainly make your own 35mm slide of a whammy, but making it look like the real thing would take a bit more work.
