Sorry but your post is simply wrong.   Anyone with an IQ of 80 and the ability to read at a 5th grade level could have done this.   Loading ammo is something a 2 year old could do.  Maybe 4 if the spring was a little tough.   Changing the stock on the gun requires an Allen wrench and or a punch.   A 6 year old could do it with the picture instructions.  Its less complicated than LEGO building instructions.   

Seriously the guy could have learned how to do all of it in under an hour.