"Boilerplate" was in use in legal circles as early as 1865: https://www.google.com.au/books/edition/Advisory_Opinions_on... - well earlier than the 1895 this article claims.

This was 20 years before the invention of the linotype machine (1884) that this author claims it was named after.

In 1896 "The Typographical Journal" did use "boiler plate" to refer to the type of printing process, but not to it being a pro-forma piece of information: https://www.google.com.au/books/edition/The_Typographical_Jo...

"Boilerplate" also refers to the branding plates that were placed on boilers that contained repeated information on every boiler. I think it's more likely the term comes from that.

It's annoying the author isn't on twitter where this could be corrected!