OK, I am in the process of putting together a post-ban SP1 look-a-like.  To comply with the law, I will have to neuter the bayonet lug and replace the flash hider with a CavalryArms compensator.  

The CavArms compensator comes with a pilot hole for driving a roll pin.  My question is, is it enough (from the legal standpoint) to "blind-pin" the compensator?  (drill a dimple on the barrel, line it up with the pilot hole, drive in the roll pin, grind the excess roll pin so it is flush with the compensator).

Or, is welding the grinded roll pin necessary to make it legal?  

Can anyone point me to the law/letters/correspondence from BATF about this?

Thanks
oz