Inherited Several 1964 Kennedy Half Dollars.

Ok. I am brand new to this - I know NOTHING. I inherited several 1964 JFK .50 coins.

I have done some research about the coin and obviously I've seen all of these crazy prices for this coin, especially on ESTY.

I have 12 JFK 1964 .50s.

Of the 12, 11 still maintain a balanced silver color and look all -- just about the same.

There is one that has turned a more gray/black and off-silver color -- it is the only out of all of them that looks like this. I took it to a jeweler friend yesterday (he's admittedly not a coin expert but he has the tools to view the coin closely).

We noticed a few flaws or signals that were different than the other 1964s I have.

1. A dangling 4 or teardrop? From what I've seen, most of the teardrop 4 coins have that drop in the front of the four. The one I have has a decent sized drop on the back side of the 4.

2. Compared to the other 1964s, it has broken rays coming from the eagle on the back side. Several ray lines either stop before they get to a star or have a break or two somewhere from where they begin at the eagle.

3. JFK's hair appears to be different than the other 1964s. It looks as if he has more of a mo-hawk, there is more space between the hair at the top, and the hair seems to touch or cross over the B, E, and R more than the others.

4. This the last thing I've been able to notice and, as I said, I now nothing. There is a flaw that I believe is called an F flow" between the F ending half and the D beginning dollar on the back.

5. With the limited magnifying ability I have, it looks like the G on the back does not have the "drop down line" on it. I know this feature has a name but I do not recall the exact term.

The potentially errored coin has no mint mark, as do the ones I compared it to directly. I have several with no mint mark and a few with the D. I did not use the D marked coins to compare anything.

What I do know is that when I put any on of the "shiny" 1964s next to the one different looking 1964 - I can see things on it that are not on the shiny one.

I don't want to jump on here and think I have an SMS because apparently that is the pot of gold everyone seems to be looking for. What I can see is that I have one 1964 that looks different than the others and seems to have some of the features that make it unique.

I guess my question is -- are there specific required error elements that qualify the coin to special, I know the things I listed above are all elements I've seen in the more rare 1964s but are there certain ones you must have, are there ones with elements that have to hit a so many flaws to make it unique or rare?

I can attach pictures and will but I did not want to start uploading a bunch of images if what I have does not sound like it's anything special.

Thoughts anyone?

Thank you.