Mystery solved? This auction just finished, and I am thinking this might be how they were intended to be distributed. The bowl looks very similar to the others I have a picture of, but the tab seems to be more able to hold the various shapes of the bases in place.
http://www.ebay.com/itm/1954-Marx-Ta...-/381536903002
And here is the picture, in case it disappears off of eBay...