These are nice images. My first thought was that it's real. Have you checked the weight? What about this coin makes it look fake? I'm still learning.
Just a word of advice, matching a coin to a specific variety is not a guarantee of authenticity. The counterfeits jloring mentioned are copied perfectly from genuine examples. So, if the original coin used was a specific variety, so will the counterfeits produced from it. As for the coin in the pictures, it doesn't look like silver to me. Could just be the photos, but the metal appears too dull.
It looks like the 2 in the date is out of proportion and style for an 1860's dated coin. The shape of the denticles on the reverse don't appear to be the right size and shape, very broad and flat rim on the left and right and narrow at the top and bottom. There are none on the obverse at all whereas for a coin in this grade it would seem the denticles should be well formed..
For comparison - while not of the same apparent/possible variety, it is an MS 62-S. Also, this date, because of die overuse, can often be found with denticle erosion.
First, good luck to you. Now, if you want to submit, it is a good way to learn, but if you decide to do so, please wait until you've done your own homework on the coin. Bill Bugert is in the process of authoring a die marriage reference set (A Register of Liberty Seated Half Dollar Varieties vols. 1-6) the first of which is on S mint coins. The books are not cheap, but nothing good ever is. You also may want to consider posting photos of the coin here (http://seateddimes.yuku.com/directory#.UrfH79J-LeE) but most importantly, don't be scared off by what anyone (including myself) says on a forum: this is your hobby/interest and will only be what you make of it.
I agree with the need to do research on coins--Lord knows the folks need to learn before they buy, and know what they have, and what they're looking for. However, none of that can be gained in a book in terms of authenticity. Fakes abound in the numismatic world, and the only way you can be decidedly sure that the coin is real is to have it authenticated by a TPG. Most really good fakes can fool marginal dealers, who will happily sell them as authentic. Ones gotten "way below market' must be suspect, as given the level of information out there on coins, people selling them know as much as YOU do when you want to buy them. Why assume they are ignorant, and will sell a $150 coin for 5 bucks? That happens extremely rarely, and less and less with the information available out there. If you think a coin may well be genuine, SEND IT IN to PCGS OR NGC, and risk the submission fee to find out if it is authentic. Makes sense, rather than agonizing over the "is it real or counterfeit" song all the time. Better yet--buy certified coins if you are not super familiar with the series. My inflexible rule is--DON'T BUY RAW, unless you know the coin extremely well, and all of its variants.
I really don't like the lack of dentils on the lower obverse. The ones on the reverse also look strange. On a coin with this much detail (full liberty, very little wear on shield), I would expect the dentils to be at least visible. I don't know about any of you, but I have a dealer in my local area with a fancy metal scanning device he uses for authentication. If such a coin came into my possession, I would go down there and see if I could get it scanned. That would be a step forward in understanding the authenticity. As others have stated, being the correct metal does not make it real, but it would be a step closer to determining if it is.
I sell coins at flea markets and you would be amazed at how many people, about 90%, who have asked me questions about their coins have said they didn't even think to try and find information on the internet when I told them the information they were looking for is there and easily found.
Below are photos of certified specimens in different conditions. The point with this is only to show that what may at first appear to be concerns or issues can sometimes be explained, and not to dispute opinions one way or the other.
That third image really does illustrate your point well. I suppose that means that I don't really see anything wrong with the OPs coin. Learn something new every day, I suppose.
The ignorance is on the part of the seller. To not know the value of the coins they sell is their loss. That's how someone can get a $150.00 coin for $5.00. Why assume they are ignorant? In some instances they truly are.
I don't see anything in the pictures that immediately leads me to believe that the coin is not genuine, and I don't think the price paid in this instance should infer that the coin is not genuine, either.
You just don't get it. The seller did not give away a $200 coin. They buyer got one that isn't authenticated, and almost certainly a fake.
Besides the price, could you let us know how you can almost definitively say that the coin is a fake?
It looks cast to me in the photographs, and the reverse lettering is crude. Not even a high quality counterfeit in my opinion.
Did you post it with or without the details of buying it for $5? Because I think that the details of cost should be disregarded in determining visually if it is an authentic coin or not.