You will find that the JDM or standard Japanese models are the ones that rust - they have always been high carbon steel. While this means a sharper and harder steel they will be subject to surface rust. The Australian models have stainless barbs as the Australian market prefers them - they are not as sticky sharp or as strong but they dont rust.
Personally I prefer the high carbon versions.
If you get a jig that is starting to rust I have found that putting vinegar in an old spray and wipe bottle and giving them a quick squirt when I see surface rust spots and it cleans them up. If left wet in a jig bag or box they will be cancerous as fu#k and rust up like an old datsun.