When new or good condition used parts are available, patching on old ones isn't a very good idea. So far as the end caps are concerned, they're just flat disc type "freeze" plugs. Cut out some discs that are a few thousandths larger than the counterbore in the spindle from 16 gauge sheet metal, place the flat disc over a socket wrench, and use a big ball peen hammer as a forming die and a vise to put some "crown" in the disc. Once it's crowned enough to be a snug fit in the hole, insert it and tap it a few times with a hammer to seat it into place.
The inner spindle shoulder wear of .002" is insignificant- - - -that's about the diameter of one strand of hair, and once the bearings are preloaded properly it won't be a factor. If it really causes you to lose sleep, super-glue a piece of .0015" stainless steel shim stock to the lower 1/3 of the shoulder to take up the slack. You could use Loctite on the wear point, but it will make it difficult to remove the hub the next time you need to pack the bearings.
Jerry
