Inside the drums, they used to have cast rings and it clear where they ran. I figured they would need a pretty smooth surface to a point to live. I didnt like the holes being not chamfered so i hit it all with some wet sand paper. Didnt want to catch anything installing seals. Just first time using teflon and would rather error on the safe side.
Sounds like you did a great job on the bore but its more important to focus on polishing the rings lands on either side of the sealing ring. The ring is supposed to spin with the drum and the sides of the ring is where the wear will occur.