I cannot tell you much about the age, But here is an idea on three of these knives if they were in mint condition:
Keep in mind that info is from "The price guide to collector knives Fifteenth Edition" by Houston Price, and Mark Zalesky copyright 2008. With todays down market with knives these values can seem pretty inflated. For example, I bought a 12829 close to the same condition you have pictured for about $450 a few months back.
All excellent Knives though