There were other companies that made their own version of Jello too during that time period.
Sears Roebuck in their grocery catalogs sold Montclair gelatin,their brand of jello.Would have to look and see if Sears sold chocolate flavour,but they sold strawberry,cherry,etc.Can't recall if Montgomery Wards also had their own version of jello,but both companies sold groceries as did M.W.Savage of Minnesota.
Not sure when Sears and Wards stopped selling groceries,but it may have been sometime during the depression.
I have a little book written by Ida Bailey Allen called Entertaining at Home,which was written for the Coca-Cola Company back in the 30s.
It has a recipe in it for Coca Cola gelatin,using a package of lemon jello and coca-cola for the liquid.It also has recipes for punches using Coke as well as other food recipes,plus suggestions for parties.Neat little book to read.
I know momma never bought the vegetable flavoured jellos.
We bought the various fruit ones though.