Based on my experience, that isn't the correct formation of the "ON" portion of the signature. There are other aspects of the signature that I also don't like, but that one really sticks out to me.
I agree Ballroom. The way the first "O" is started looks unusual as does the "S" to me. It just doesn't look or feel like him as an overall. Would you say its definitely a fake? Also the dark dot on the second "S" which appears to be a stop and then start again. Always value your knowledge on Jim's items…. Cheers