I'm sure there are pocket knife collectors out there that can give you an idea of age, but for that I'm not much help.
As for the preserving the wood I've used the boiling in paraffin wax on iron items with wood attached.
Clean your item up to the point you would like it to be preserved.
First I soaked the piece in rubbing alcohol for a few days to displace the water in the wood.
Take it out and let it dry.
Then stored the piece in silica crystals for a few more days to remove any left moisture.
Don't rush drying the wood it can hold a lot of moisture and will crack if not fully dry.
Then I boiled it in the wax.
Supper care needs to be used when boiling wax!!!
Use a super deep container so it cant boil over and don't let it get to hot.
After your item is dry it can be preserved in wax.
Heat your wax up to around 200 deg. (use a candy thermometer).
Use just enough wax to cover the item by about 1/2 inch it doesn't need to be too deep.
Use tongs and slowly lower the item into the wax.
Bring the temp up to around 220 deg.
You don't want it too hot and boiling to fast. The steam boiling out can split the wood also.
Watch the bubbles and when they stop, use tongs to remove the item and dry it with paper towel.
Be Sure to use thick gloves... It will be HOT!
Let it cool and buff it with more paper towel.
Done..
Here's a YouTube video.
Don't know if it is aloud to attach..
I think it could be a little older than Terry does, maybe 1930s, but agree that it isn't worth doing anything with. Unidentifiable pocket knives are common finds and I long ago and still do throw them in the trash with other rusty iron junk. Likely not German made since a common trait of German pocket knives is that they use steel pivot pins in nickle silver bolsters.