Threading the barrel is easy, but swapping front sight bases is more involved.
Is your new front sight base un-drilled?
That makes it easier.
The issue is that there is no standard location for the pin holes.
When a barrel is made, they pin the fsb on to it while it is all fixtured up.
Then they never take it apart again.
I specialize in AR work and can do everything you are looking for, but I would not take a front sight base swap to most gunsmiths as they will not have a specific fixture to ensure that the job is done right...