Insufficient evidence at a prelimminary hearing is not a dismissal. The odds are,that unless the cop only made a technical error in paperwork, or forgot to bring something with him,he will not re-file. It does NOT mean he cannot re-file. He can re-file in a N.Y. minute,as long as he has "just cause" to do so.
If the case goes to a court,it looks bad for the prosecution to have this mentioned in court,but it also does not mean by a damn sight,that your going to walk away either.
I have a friend doing 3 years in State prison,after being tried three times.He really was guilty as sin,and everyone knew it,but it was technical crap that kept getting him off the hook. Three times being the charm,the prosecution finally nailed him.