When building AR lowers, scratch the blem lower, not the good lower.
I almost want to bitch about Palmetto State Armory having a poorly machined selector detent and no buffer retainer in one kit. Then, I remember one Armalite kit having an AR-10 bolt catch in it. Now that is a big mistake. The ALG QMS mil-spec triggers are nice, though. Even included a shorty pin to install the trigger and disconnector as one unit.