I was wondering if those who are familiar with Buster Keaton's handwriting might be able to take a look at this. It's a close up of an old album page from the early 1940's with some other names penned on the verso.
I have a Keaton with PSA that has similar letter formation and spacing as yours. Buster was pretty consistent in his autograph. I think yours would likely pass a TPA. Also a nice Douglas Dumbrille on the back.