I guess this aging process is soaking newly made harness in boiling water. Adding dirt, sand into the pan, like cooking
The rod looks replication too.
Spring could be original, but it's a common 5-v spring, not 4-v. I have waited spare 4-v spring for a few years, none available. Once saw one, looking at detail -- it's a broken 5-v
One collector asked me: why not just make a 4-v from a 5-v? Well.... no fun that way.
Still looking for 4-v spring. Also hard to find a donor gun to donate this spring, gun went to donor status today usually had that spring replaced long time ago. Nice guns have that spring, but they are not donors.