Unless you have an eye for autographs, there is no way to explain "obvious giveaways." Forgeries are meant to have the "appearance" of being authentic.
The forgery business/industry today is bigger than ever today.
For some reason, people think that Ebay filters out the forgeries before they are listed; nothing could be further from the truth.
Never seen Dimaggio co-sign anything Mantle...I will admit this one will fool even some of the most trained eyes like myself...but one thing that the fakers never get right is one letter with the formation almost no faker can accomplish and for that i will say no good...but i will also say this a fake that is undoubtedly above adverage...