The problem with used, lots of folks don't/didn't take very good care of their firearms.
Look at the bolt lugs for galling, pull the action out of the stock and look for rust pits in areas that never get pulled....if you can get the screws out, might be rusted in place. Haven't even mentioned barrel or muzzle wear.
But if you can find an old one for cheap, you can always use it for a build!
And if you don't mind waiting for what you want, buy it one piece at a time, and eventually you will have exactly what you want.
Pick a good 'Smith, too!
"The People of the United States are the rightful masters of both Congress and the Courts, not to overthrow the Constitution, but to overthrow the men who pervert the Constitution." - Abraham Lincoln
it's [beeep] to grow old......it's [beeep] not too