IF the rifle has not been fired too much AFTER it was inspected, then you have a very good one. The stock disks give an indication of the bore condition, but that is subjective. Unscrupulous people can easily change a disk, and misrepresent a poor condition rifle for a better one. Also, new knock off bore disks are available on E-Bay and other places.
This disk would indicate a rifle bore of 6.49 mm as noted. Husqvarna made m-38 rifles had a maximum tolerance of 6.51 so the 6.49 bore is VERY GOOD. The other indicator is that there is NO punch mark on the "1-2-3" pie shaped area, so that suggests that there is no rust or imperfections in the bore of the rifle. (Rifles, even with a 3 bore indication, still tend to shoot well --but after a 3, the barrels are usually replaced.)
If the bore disk is correct for that rifle, you should have an almost perfect bore and a LOT of good shooting from that rifle.