Try putting a bit of leather treatment on each part. If it soaks in, it's leather. If it doesn't soak in, it's vinyl.
I like Lexol Vinylex or 303 Protectant on vinyl. I tried some Chemical Guys leather cleaner & treatment. Works OK, but the fake new-leather smell is too strong and lasts way too long. Lexol Leather treatment is tried & true, and I like Leather Honey for heavy duty treatment. Leather Honey is goopy like honey, so it isn't a quick job.