This doesnt look authentic to me. I am pretty familiar with Slash and his signatures and their are several things that dont look right here. One is the skull itself. Its better than most fakes, but still doesnt look like his style. The first S in slash is also a concern, and the formation of the overall signature looks wrong to me. I could be wrong here so you might want to wait for others to chime in. But i can say that i wouldnt buy it.