Here's an E121-80 Mays I "borrowed" from Bobby's VCP site.
I don't know enough about E cards to tell you if the one on ebay is authentic. But I believe E121-80's were issued in 1921.
And I have a W502 Carl Mays available for sale somewhere on the BST ... send me a PM or email if you might have an interest.
Best Regards,
Craig