Now, I do have to admit, those struts make them look like Mini-A1As that I do like that look. But no need to spend money unless you need to.
3" - 4" open sights at 100 yards is very good shooting. If your groups where similar in shape every time then your firearm is accurate and you just need to work on precision with maybe a scope, trigger job, etc.
Keep us posted. I only shoot my Mini 14 open sights and at silhouette targets at about 60 yards while I am free standing. Can put an entire mag in the head area of the target. It does exactly what I want it to do.