I think it is Borje Salming. He is a Hall of Fame former Maple Leafs defencemen. The only thing off in this signature is that it doesn't end with a downstroke for the "g" at the end of "Salming"...but I have seen him do this before.
Yes, I do think it is authentic. It looks like an older example of his signature, but the flow and formation look absolutely real. Plus, there aren't a whole lot of people forging his signature.