I have never seen a Knoblauch signature that, uh, er, nice. Usually, his signature is an unreadable mess with no separation between the first and last name. Granted, this could have been a paid deal where Chuck took his time and signed all 500 bats cleanly, but I have my doubts. I question whether the inscription was added by Chuck. I doubt that Chuck would have been asked to add 392/500 and the 9's in 1991 and 392 look to be from the same hand.
From my experience younger players tend to sign with a full signature (see how Cal Ripken's signature has changed over the years). So, it is possible that that the bat was a signed after his rookie campaign. I agree that there is little money in forging Knoblauch signatures.
If he signs like this for Steiner
https://www.steinersports.com/chuck-...-roy-insc.html - I would want more of a background story.