Looks like paper tablets even predate that 1902 use. This source has newspaper ads for "Pencil Tablets" and "Writing Tablets": bound ruled and un-ruled paper with and without covers from 1894-1895: https://www.kristinholt.com/archives/3205

I wonder if binding at the top was necessary to be called a tablet? Or perforation to easily tear off sheets?

I was looking to see how long ago marble composition notebooks (which are side-bound) were created and what they were called and it looks like they existed in the mid-1800s but I couldn't find any evidence they were called tablets.