NO, it does not sound like a SAM. No eyewitness reports of such, unlike more than a hundred reports of rising light and smoke with the TWA 800. NO eyewitness reports of such is more amazing, since we have had numerous conflicting eyewitness reports, such as the one guy who said he saw the tailpiece in the water(sounds like a hoax, would have seen more of these reports, would be aware of a sea search by now).
So forget the missile theory.
No flaming datum, no very heavy smoke trail, no very loud missle launch noise = No missle. You are right.
Would be tougher to see during the day tho..Flight 800 was at night so one would easily see the missile. Maybe it has do with the fact that thousands of people have been laid off and maintanance of these planes is not what it should be.