Uncle Vanya wrote, "Brunswick''s advertising was a bit of a confusing mess. They retained the "Light Ray" designation long after the Palliophotophome mechanism was replaced with a conventional condenser microphone."
This may be true for print advertising and record sleeves. However, for what it's worth, on page 20 of his Brunswick Records discography, Ross Laird asserts that the "Light Ray" designation on Brunswick and Vocalion labels only appeared on West Coast pressings from late 1926 to late 1927. If this is so, you could easily have a Light Ray process recording with a label that did not note this. See:
http://tinyurl.com/lr7ob42
Or, to give you all confidence about the above link, here is a preview TinyURL:
http://preview.tinyurl.com/lr7ob42
Since your disc does specify "Light Ray," according to Laird it would be a West Coast pressing. But perhaps as Uncle Vanya says, the Light Ray designation was carried over on West Coast pressings after the Light Ray process had been abandoned.
(Distortion or not, that version of "Shake That Thing" is one of my favorite 78's!)
Best wishes, Mark