Dating boker knife
First of all, let me start by saying this is a work in progress.
We know how difficult it is to determine the age of a Boker knife.
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It appears to me that almost all of my pre- 1970 Bokers have ringed bolsters.
Your shield was used into the 70's and some sources say the 80's on the Boker imports-- However, I found a PDF from the early 70's showing the Boker catalogue--- Although, some of the German imports were still shown with a shield like yours, your 5452 model was shown with the newer circle shield- All of this tells me your small congress is circa 1960's- Ricky may have other ideas, but I would date it to the 60's.
I am certain that there are other collectors who can add to this list!