Hello,
Here I have a registered letter and envelope from Nov 1920 - the stamp on the envelope is gone, it looks like it got wet and fell off or was taken off. Here is the cover:


There are 2 cancels on the back of the envelope, but they are quite faint on part of the cancel, you can read the town however, and that the letter was registered - you can see the registered number on the front of the envelope. I am wondering if this is of any value to to anyone, especially since I have the letter, here:

The letter is the only way of dating this cover I think. The letter is from a smoke shop in Madera California to Miss Mary Madruga in Sausilito, CA.
Does this have any value at all since the stamp is missing? Any help with this would be most appreciated. Thank you, Julie