I received these photos from Ron of his mother's late 1930's Tappan stove. The back splash has the "opal glass floodlight", as well as a timer and Visiguide.
I have included some marketing pieces below from 1940. The 640 model (second to the last picture) is very similar to this stove...except you will notice that the 640 has lift release buttons to open the storage compartments on either side and Ron's stove has turn knobs (indicating it's an earlier model). You can see in the marketing materials, the back splash varies slightly from model to model as the design evolved.
I love the charming red details on the burner knobs and oven/broiler handles! Tappan also must have liked this detail because they used it in a number of the marketing pieces below.
Ron is looking for a new home for this stove. If you are interested, contact him here for details.