I haven't had the need to take mine off and check the treads, but I'm kinda guessing that the treads will be one of three common to most muzzles.
What is your concearn with the one that came from the factory???
Any flash hider threaded 9/16 X 24 Left hand or FAL flash hider will work. but the thing you need to take into account is the second notch in the barrel about an inch back from the threads that needs to be covered for asthtic reasons I installed one of these on a customers gun and it turned out pretty well.
If you need a factory FS2000 FH the browning repair center may still be the only place to get it.