Are barrels finished better or worse than they would've been from the factory? To know this, you'll have had to do a fair amount of study with other examples of the makers guns. Most guns that I have had the barrels refinished, the barrels actually turn out to be much better than they would've been from the factory. The degree of polish, the sharpness of the engraving, the polishing strokes on the lumps, Those are good indicators too. In regards to blacking remaining on the flats...a lot of makers left the flats black. You should change your "rule" if that's your criteria for refinished barrels.
A biggie on guns of English make is the "sheen" of the blacking. Most metal finishers in the U.S. believe that the proper sheen for barrel black is a non-glare, satin type finish. To me this is a dead giveaway for a U.S. barrel refinish. If the blacking has too much of a "gray" color too it, not right. If the barrel lumps are polished horizontal rather than vertical.
There's all kinds of indicators out there.
