Check the serial numbers on the rifle, just about every part on a swedish mauser is serialed, except the screws. The ones that are the most important are the numbers on the receiver and bolt body- they should match, if a rifle was rearsenalled and given a new bolt at a Swedish arsenal, the bolt would be stamped or restamped to match the receiver. If they match, its very unlikely that you will have excessive headspace, unless some civillian did a poor job of changing a barrel afterward. Pull the bolt and look down the bore- it should be shiny with crisp rifling, if not, run a few patches down the barrel and check again. If it still looks dark, I would pass it up, the rifle has been abused or neglected, two things the Swedish never did with their rifles.
If it has a stock disk, there should be a little triangle stamped over certain numbers indicating bore condition and diameter. In the big pie slice, a marking of 9,0, or 1 would be desirable, in the small pie slice no marking or a marking of 1 wouild be best. Its nice to have a disk marked as such, though I wouldn't put too much thought into it as the disk might have been last makred 50 years ago and alot could have happened since then, or someone might have unscrupulously changed the disk to make it look like a more desirable rifle.
$125 is a pretty good price for a rifle in good condition with non-matching serial numbers, its a steal for a rifle in good condition with all matching numbers.
