They go back further than that... At least from before 1900.
They were called ice cream forks, and were often included in the large complete silverware sets that came in fitted cases that were so popular until the last quarter of the 20th century.
Have you ever tried to eat HARD ice cream with a spoon? It tends to shoot out from under a normal spoon. A Grapefruit spoon is somewhat better, but still does not hold the ice cream completely under the spoon... But a spork works perfectly for the job... I have old 'general knowledge' books that show them in silverware sets.

P.S. I wish they would still write 'general knowledge' books. They were so useful...