trail, that is awesome!
I have only seen one other Boker Barlow with a ringed bolster like that!
Here's a pic. Note the saw marks match yours.
All the catalog evidence I have seen for pre-WW2 Boker barlows have ringed bolsters, but they don't have a tree on them They have BOKER in block letters.
In the early 1950s catalogs, both a ringed bolster and smooth bolster are shown. But I don't know if that indicated sawed bone vs. smooth, or a 492 vs. 493 pattern. I suspect the former. But again, there is no tree on the early 1950s Bokers. They have "BOKER" in a cloud, with "Made in USA" above.
Here's a sample.
I don't find evidence of barlows in the 1960s catalogs I have. That doesn't mean they weren't made though. I strongly suspect they were.
I'm wondering if the ringed bolsters and tree combination like yours might indicate a late 1950s - early 1960s knife.
PURELY speculation at this point.
Thanks for sharing that one trail!
Are the handles on your 495 bone? Is the 493 delrin?