Is All Meladur a Wright Design?  

Meladur Melmac: Originally Russel Wright, GATX, then Lapcor
Hello,
In response to your question I have done 25 years of research on Meladur and Russel Wright melmac. You can find the whole history on the link below, but in a nutshell, most Meladur was a Russel Wright design *with exception of the completer pieces such as cream, sugar, trays, divided bowls, and redesigned mugs which never bore his signature to start with.
Originally designed by Russel Wright as a test line for American Cyanamid circa 1945-1946, Meladur earned it's official name and then was produced by General American Transportation Company (GATX) and sold only sometimes with signatures. This was between 1947-1954 *during which time there were many pieces produced without signature due to contract disputes and fallout*, so it is entirely possible to have his design with a generic General American signature only.
To make matters worse, the molds sold to Lapcor of Manitowoc Wisconsin around Dec 1954 and had that backstamp. I've even found similiar designs from Canada and Austrailia which I've shown on my website.
So your bowl, if a sugar, cereal, or veggie with scalloped feet IS indeed a Russel Wright design. Collectors like me get used to seeing a set of half marked half unmarked, and because I know the history, I know what a mess things were.
Here is the link, and a photo of my dishes.
Enjoy
cindy / ira mency
http://retrochalet.blogspot.com/p/russel-wright-meladur_08.html

I've always loved these
I don't have any knowledge to pass on about them, but the stuff in the above photo was the dishware of my childhood summer camp. Just seeing them brings back some of the very best memories of my childhood!