The large section of the disk indicates that the bore is pretty tight, 6.48mm. Should be good for a lot of shooting yet.
As far as the wear marking, I've seen rifles with a 3 marking on the wear section that still shot very well. The Swedes were very picky about maintaining their rifles.
Of course, all this assumes that the disk is the one that is actually matched to your rifle and that the rifle hasn't had a lot of use since the disc was attached.
The third section has to do with correcting the sights for the newer 139gr bullets as opposed to the old 160gr bullets. I don't think it really means anything on the Ljungmans because I think they came along after the 139gr loading was being issued.