I obtained the signature in person and its 100% authentic. It comes with a JSA Cert# WP273332 & Beckett Cert# 112005 that can be verified on their website. The item "Oakland Raiders Marcus Allen & Bo Jackson Signed Combo 11x14 w JSA/Beckett COA" is in sale since Tuesday, May 9, 2017. This item is in the category "Sports Mem, Cards & Fan Shop\Autographs-Original\Football-NFL\Photos".
The seller is "citygraphs16" and is located in South San Francisco, California. This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Indonesia, Taiwan, South africa, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Israel, Mexico, New Zealand, Philippines, Singapore, Switzerland, Norway, Saudi arabia, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Brazil, Chile, Colombia, Costa rica, Dominican republic, Panama, Trinidad and tobago, Guatemala, El salvador, Honduras, Jamaica.