I discovered the Russell Belt Knife in the last half of the nineteen fifties while attending high school in northern Ohio. I don't remember now whether I first saw the knife in a magazine advertisement, or in a sporting goods store. Given my close proximity to lake Erie and Canada, it may have been in a shop. Having an interest in art, I was very impressed with the design which was quite different from the knives we then had. Naturally I wanted one. However at this time I had also discovered automobiles and girls, both were then, and still are, high maintenance items, so the Russell Belt Knife had to wait, along with the Buck and Randall knives that I also wanted.
I got my first Russell Belt Knife 1971/72, a #2 Trout & Bird Knife in Carbon Steel, and have used it over the years as a general use field knife, primarily field dressing small game with a few fish thrown in. Although I have never used it on anything larger than Javelina, I found the design to work very well. In the years since I have added a few of the #1 Original Design Knives, and like them also.
Due to my interest in these knives I became interested in their history and began keeping notes on them about five or six years ago. With that said, I will offer my thoughts and opinions in an effort to answer the original poster's questions.
According to Grohmann they began manufacturing the Russell Belt Knife in 1957, This was before the design was registered in 1958. Please understand that I am referring now to the #1 Original Design Knife only. After the design was registered the knives were marked,
Right side of the ricasso/tang___ 'Rd-1958'
Left side of the ricasso/tang____ 'Russell/BELT KNIFE/Canada'
The design registration was issued for twenty years, so the knives were marked as above from 1958 to 1978.
Now we can consider the first year of production, 1957. At the present I do not know for sure how these knives were marked. It may be that they are marked as above without the 'Rd-1958', and I do have one knife in my notes that is so marked. This knife could be a 1957 production, or it could have been made after the registration expired in 1978 and before the next ricasso/tang markings were implemented. They were marked,
Right side of the ricasso/tang___ Blank, no markings
Left side of the ricasso/tang____ 'DHRussell/BELT KNIFE/Canada'
Note that Grohmann's name does not appear on the above knives. I have cataloged a total of eight different combinations of ricasso/tang stamps and blade markings and still may have not seen them all. Grohmann is on all of the subsequent ones.
The only method I have of dating these knives is the memory of the owner's as to the year they purchased them, or original sales receipts. Then a general time period may be established.
I hope you find the above information, if not useful, at least interesting.
If anyone has any questions I will try to answer to the extent of my knowledge, they are interesting knives.