You can do it. A high mount scope does have a disadvantage, nothing to do with it being an AR. It forces a trajectory into a rainbow pattern, because the barrel is about 2 !/2" lower and actually has to shoot up to the point of aim at closer ranges. After the mid point, it falls further.
Imagine if it was 36" above the bore, at 100 yards the barrel would be noticeably tilted up. On the AR handle, it will expand the normal 3" group that you get out to 300 yards to string a 6 or 7" group at the ranges in between.
Sighted in for one specific distance, it's not a major bother. Making up a range chart to know how much elevation to dial in and correct it is normal for precision shooters anyway. Live target shots are where the flattop is preferred because it won't have as much vertical spread.