Honestly, on older Rugers I worry more about salt wood than barrels, as I do own two "salties", and have seen others.
I have owned or worked with a little over 20 #1's of all vintages. Some were more accurate than others, but I personally have never seen a stinker - one that would only do 2-3 MOA at best. I am sure they exist, but they are not common. I think most of the stinkers by now have been rebarreled. I will allow that I've never owned an International, nor any red pad 1A's until recently, so perhaps the lighter/band on barrel guns were fussier.
I now have a #1A 7x57 Liberty model, which I have not yet shot. It has very consistent good looking grooves and lends, but plenty of reamer marks inside the barrel. So I guess we'll see how it shoots. Ruger seems to have figured out that good barrels are essential, which is one of the best things they have done in the past 20 years.
Making good barrels should not be a mystery, regardless of the process. Good & consistent heat treating, dimensional accuracy and smoothness. When a tool gets a little worn/dull, replace it. If the priority is lowest cost, then people are going to push the tools as long as possible. If the priority is barrel quality, then the barrels will be better & more consistent.
