So a follow up question. Is this seat post workmanship a problem for whoever winds up with this bike?
One of the framebuilders who post here will be able to give you a better answer, but if it were my bike I would drip a little epoxy in that gap to help prevent water from getting in there and causing corrosion. I suspect that there is enough area brazed together to ensure that the seat lug doesn't detach from the tube.
I would also see if I could find the washer that belongs under the nut on the seat post clamp so that the nut doesn't continue to grind up the lug.