I cant say with 100% accuracy but it looks solid. I worked for Paul Newman at "The Hole in the Wall Gang Camp" in Connecticut in the summer of 1988. Let me tell you he was a nice, friendly guy. He would talk to you and have pictures taken (Also liked to drink beer) But let me tell you I was one on one with him for a while and he simply would not sign for me or any else. He simply said " I don't sign autographs". Joanne (His wife was the same way). I also used to see him at the Indy 500 over the years and ironically he would sometimes sign there. It was my understanding he would sign racing related stuff. I have seen a few helmets and racing photos even a racing program or two. But since this is a racing photo I would say your odds have increased significantly.
Anytime you say "I can't imagine a forger doing [x]", you've found the reason that a forger would do that thing.
Not all forgers are stupid/lazy--some are smart enough that they realize that, while a nice, clean autograph will yield big money, that'll get them found out sooner. Less desirable autographs will yield less scrutiny, and, overall, more money.
Always, always, ALWAYS judge the autograph on its merits, not the perceived motivation of a forger.
See, that's why this is so much fun.
Something like "Steve" or "Mike" wouldn't alienate a decent segment of the population like something like "Slim" would.
But that's exactly why you would choose "Slim" over "Steve" or "Mike"--by alienating a decent segment of the population, you get the rest to let their guard down.
I started thinking about this when I was reading a discussion (possibly on here) about Idina Menzel's Broadway stage door autographs. She was so rushed that the "signature" was little more than a squiggle, but people were still buying and selling them (generally extremely cheaply) on eBay.
I realized that, with the high price her full, real autograph commands (and the scrutiny that comes with it), a forger would get themselves caught if they tried to sell a couple (say $1,000 worth) of them. But, with the number of squiggles she signed every night, nobody would bat an eye if they sold $1500+ worth of those.
We all know "if it seems too good to be true, it probably is", but a lot of people tend to forget the mantra of the other side of the spectrum: "or is that just what a forger wants me to think?"
"Nobody would forge a personalized & faded autograph on a shredded piece of notebook paper when there are so many more pristine alternatives available on the market..."
"...or is that just what a forger wants me to think?"
The smart forger knows that they can make a lot more money overall by flying under the radar & selling a lot of appropriately priced low-to-mid-grade stuff.
I prefer dedicated inscribed photographs! So much more words per $ and so much harder to forge! Also, the potential for content/context!