Louvre and Glasbake ad in January 1937 issue of Pottery, Glass & Brass Salesman. The so-called Flamingo bowl is the upper of the two bowls.
What makes the non-flamingo Flamingo bowl even more of a puzzle is that it appears to be identical to the Verlys Wild Duck Bowl shown here: http://chataboutdg.com/gallery/details.php?image_id=10241
How McKee got access to the Verlys mold is unknown.
Tom Felt found a report in the Crockery and Glass Journal, October 1936, showing this bowl and calling it "the Flamingo." It sold for $1.75.