I have never seen anything like that. That space after the first "r" is very unusual for later sigs. I just read over the Sinatra studies I have saved and as many examples as I could find - nothing close. When was this said to be signed and who is selling it? The second "a" is upper case? That is odd. The first name is signed much smoother than the last name. Strange.
Is there some sort of provenance of later years?
This is his gun permit from just a few years before his death in 1998: