First you don't file on the ladder, you file on the bottom of the sight.
Its no different then shortening the front sight or changing front sight post on the 1903's.
Or going to a wider sight on the 1903s (since the Marines modified the front sight to .07 which is about the same width as the Garand.
All these alter the rifle from as issued.....
You want to shoot lower without altering the gun? A tiny bit of black electrical tape or appropriately sized black tubing around the front site post to make it taller.... trim to length needed.