Those that cut off the top of the Colt’s sear block - was it necessary to refinish the metal or it doesn’t matter since the bottom of the carrier is usually lubed?
Does it look ok with the finish as is after the top is cut?
Thanks.
It’s going to be bare steel where you’ve ground it. I suppose it might rust if you’re in that type of environment and don’t keep it lubed. The finish will be whatever you make it. You could probably polish it to a mirror finish if you wanted to. 
But since it’s inside the lower, no one will see it anyway.
Cutting it will allow you to run a normal bolt carrier but it’ll still restrict your trigger choices and it’ll still be a PITA if you’re pulling FCG out.
The real fix is to grind the whole thing out or send it to ADCO and give them $50 to do it for you…