Now that I have time, I wanted to come back and show you why your signature is not authentic (and IMO this should be done anytime someone condemns a signature as long as they have time)
You can see from the image posted below that your letter has the same signature. That is because it has been mechanically reproduced, more than likely by an autopen. You might notice very, very, very slight differences in autopen signatures. That is normal and is typically caused by one of the following:
1. The signature matrix wears down with use causing minor differences
2 a human being loads the item to be signed and moves the item slightly during signing
3. An autopen can hold various writing implements so different implements have different tips, flow rates, etc
Best wishes and still a neat family item
