I've never seen a FA with a front sight base that was screwed on. Every one of the many many hundreds I've ever seen has been soldered . If you do indeed have one which is screwed on, it would be worth contacting the factory to inquire why, and get a letter.
If you mean removing the front screw that holds the blade in place, obviously the blade slot will still be open and will look awful. The later generation of hooded front sights, utilizing a post instead of a blade do have a couple of screws, but the base is still permanently attached to the barrel.
I've ordered a number of FA's over the years with the "No Sight" ( and of course, therefore, no base ) option, in those cases where I knew I would always have the gun scoped. It is a clean look which I like, but you can't get that with the question you're asking.