[Semitar6]

My grandfather was a huge collector of all kinds of merchandise and when he passed, I came upon a collection of baseball cards of his. I noticed one card that was a bit different then the others. The card stock is thicker then a regular card as well. I understand this could be a rare card and that there is only a few examples known to exist but how do you tell if the card is authentic? The card is approx. 3.5 in. long and 2.75 inches wide. The scans arent great because its enclosed and I didnt want to open if if I could avoid it. First let me say, I doubt the card is authentic but we are located a very short distance from Adrian. Although Im a fan, I'm not a card collector so go easy and I'm aware that I'm not knowledgable on the subject. I am curious to know, if there are alot of fakes of this card out there and what should I look for? Any information would be helpful. Thanks