I don't know his art well, but in my opinion the signature and inscription are not by Michael Jackson. While it's close in parts, look at the ink flow closely, and you can see stops and starts. That leads me to believe this was likely traced. Have you checked to see for sure if it was sold by Julien's? Memorabilia Vault has provided false provenance in the past.
Looking at the ink flow closely, you can see stops and starts. That leads me to believe this was likely traced from a g