And now I see the same seller has listed another one with the exact same pictures and description. I'm sure it's possible that they actually do have more than one, but I sure hope the one you got is an original.
I just got it in the mail the other day. I'm fairly certain that it is original. It looks and smells old, to be quite honest. It has that odor that an old magazine gets when left in a basement or attic.
The paper stock is quite thick, and is shiny, not porous like copy or printer paper. It looks original to me, this is actually the third one that I have seen this seller selling.
I'll make some scans soon and post them. Most of the ads are ones we have all seen before. An interesting one is an advertisement for "Wild Western." There are also numerous different fonts for the word "Colecovision" that stores could have used in their advertisements. I'll try to post them soon....