I suspect that line boring would merely increase the clearance particularly where the tubes are misaligned.
I suspect that a decent adjustable 1 inch reamer with a sufficiently long pilot as recommended for over half a century is best, then second because of cost, line boring the assembly with new bushes.
Hard chrome has extended the life of the kingpin/bush assembly considerably. Combine that with protective gaitors over the bottom bush/spring area and one has gained an acceptable service life.
