I've bought two Bergaras that had rust and pitting in the barrels out of the box.... problem is that they both shot one-hole groups with my loads. They both had similar scaling like what you're seeing inside the bores.
Stainless steel bore brush, Sweets 7.62, VFG pellets with Kroil and JB, I scrubbed the heck out of them and the scaling went away. The rifles don't shoot any worse after the aggressive cleaning. I'd prefer my barrels not have rust pits and nastiness in them, but until these barrels stops shooting why worry about it? Cleaning method was recommended by the manufacturer, I was nervous about it but they came through fine.
I scope my bores with a Teslong hooked up to my laptop so I save the pics and videos with the date on them. I scope barrels when they're new, before and after cleaning to see the change, and randomly along to way to build a record of what the bore looks like. If something ever goes bad with the gun I'll scope it again and look for what changed. When the barrel gets to the end of it's life I'll scope it one last time.
I don't know another way to figure out what does and doesn't matter when scoping a bore other than doing it a lot and waiting for the rifle to start shooting poorly. Until I know what matters I'll keep doing it and building a record.
This doesn't mean I'm not still mad at Bergara over the rust - I've seen smiths pull barrel blanks out of cabinets that have been sitting there for months in the heat and humidity without a spec of rust in them. Bergara should be able to package a complete rifle in a way that they don't rust before they're sold.
