I grew up in an era when NRA 'standards' were used to classify the external and internal condition of a used firearm.  The grading (which I internalized) ranged:  New, Perfect, Excellent, Very Good, Good, Fair, and Poor.  These conditions were well defined and printed in the Classified Advertising Section of each copy of the "American Rifleman".  These standards were also applied to 'bore condition'.  Used gun values were determined by where a 'specimen' fell in condition rating.  Of course, there were rifles that appeared 'mint' on the outside, but had a rotten or damaged bores.  Conversely, there were rifles with rough or damaged exteriors, but they were 'mint or excellent' internally.  These hybrid condition arms would be more subjective in valuing.  Also problematic and subjective was the arm that had been modified (by skilled gun smith or Bubba) and was no longer 'factory or arsenal correct'.
Nowadays, there are a lot of vague and contrived terms thrown about which smack of Madison Avenue:  "Strong Rifling", "Duffle-Cut", "Excellent for its age", or (the visual photo of a bullet inserted at the muzzle).  These practices 'spin' reality and obscure or hide actual damage.
     In my opinion, a gun buyer needs to give primary attention to the condition of the bore.  If it is dark, pitted, and rough (after cleaning out lead, old dried grease, or cosmoline) it will probably remain that way.  It may be able to shoot accurately, but it will probably be very fussy about loads, bullet selection, and weight.  It may shoot like a 'Brown Bess' with no discernible grouping and bullets 'key-holing'.  Also, a lot of money and sweat will be expended in 'cleaning' after Range Sessions, with non-satisfying results.

Couldn't have said it better myself. Never has caveat emptor been more valid than now, in the age of internet buying.

45 years of messing with Krags, and I use bore condition as the determining factor when buying one as shootability is a prime concern. Nothing breaks my heart more than if a pristine example turns out to have a sewer pipe bore. I'll lay it down and buy its brother that has a few condition issues but with a pristine bore- no matter whether it's a Krag or a Sako.

As an aside, one of the most gee-whiz accurate Krags I ever owned was a '96 carbine with a rather rugged looking bore, that was given me by a widow lady. That thing would slop 220 Hornady's into 1½MOA all day and all night. Probably should have kept it...