Fivem 6351?

[Psychopath]

Task Manager > Details
That's where you see all the executables and their full names.

As @yimosecai mentioned, if it doesn't have a build number at the end, FiveM (Old) is the one you have to inject.
It is safe as long as you won't get recorded or abuse the cheat. As long as you are smart with it, you should be fine in the long run.
However as always, our cheats are undetected, but not undetectable, so keep that in mind. We can't predict the future.