Behold patent US147119[0], issued 1874, nearly a century before Taco Bell existed. The specific word "spork" was common enough to include in dictionaries just a couple decades later.

Hilariously, if you do an google ngram search for "spork,foon"[1], you'll find that in comparison, foon is incredibly popular, completely drowning out uses of spork.

I looked at the book results. It's apparent that the ocr has misconstrued ye olde "s" as an "f"; a mistake I also make, on those rare occasions I read something printed before 1800 or so.

[0]: https://www.google.com/patents/US147119

[1]: https://books.google.com/ngrams/graph?content=spork%2C+foon&...