We have a min shop fee of $35 for upper work.
It sounds high, but its not because of the liability we have when we touch things other people have assembled. (I'm not saying this is the same thing, but....) Many times we're the last resort after people have hacked away and damaged things and even some uppers we see come out of the bigger mfg's were slapped together improperly so there's always a risk we take messing with it and things could possibly get damaged which we would replace, etc, etc.
If you'd like to get your moneys worth out of the $35 bring the muzzle device and rail system and we'll get everything installed properly at one shot.