Eames lounge chair and ottoman  

Sure, but I know a real one when I see it.
If you do, too, go ahead and buy it if the price is right.
When you sell it, you can demonstrate its authenticity to potential buyers through photographs of the bits that you looked at to convince yourself.

many...
many of the 1970s-2000s models labels are a simple sticker that could easily fall off. and sometimes I have seen a few models when the receiver of the chair, often given as a gift...removes the label, like you would unwrap A Newley bought item, some people think it should be removed. Foolish...yes. It happens.

We don't need no stinkin' badges!
Most anyone willing to pay the going price for a nice vintage ES670/71 wouldn't rely much on a sticker or two under the chair anyway. Don't worry about it. There are plenty of details that differentiate "originals" from knockoffs. If you're confident in your own level of connoisseurship and market savvy, go for it!

Thanks
For the advise. Didn't pursue it even though it was a super deal. Didn't feel comfortable sending someone a lump of money in hopes of receiving the chair as promised. It was the oddest craigslist sale I have ever come across. Someone conducting there own private 5 day auction via emails. I imagine that at lead a few if you must have seen the add. it was a Chicago listing.