More that the signature is "San Antonio Spurs" whilst he is playing for the Knicks on the card.
The Silver signature is the same as the gold version.
I don't think Herb every played with the Spurs?
I think it may have also been down to UD not having the rights to depict the players signature...... Grant Hill had "Detroit Pistons" on his as he had an exclusive deal with Fleer for his auto (even though this is a facsimile) so UD if they didn't have an example of the players auto or couldn't use it just went with a team name.