fixed sighted guns needed to find a load that would shoot to point of aim. If the accuracy wasn't acceptable, then file the fixed sight down (alter) to get the point of impact where you want it. That load stays with that gun from there on out.
Fixed sights are for reliability and simplicity on a working weapon. Adjustable sights are for paper punching or playing with different loads.
I know that I use the sights to line up with my load and if the accuracy is good enough, they never get changed again. (until the screws back out...)
Bottom line is sights can be changed. If adjustable will not slow you down or if you shoot a lot of different loads, they will be fine. Otherwise, find a load your present sights like or change to a different front post.
Good luck
