Well preserved knife. I had guessed that the knives with etched pattern numbers were newer than the ones without pattern numbers (well preserved without pattern numbers, not worn off). But it's just a guess. Would be interested in hearing more about your theory.
Actually, theory may be too strong a word for what I was thinking. It is more of a feeling, or a guess, based on a small sample size. I also believe that the knives without pattern numbers (well preserved without pattern numbers) are earlier knives as well. However, I was kind of lumping the no pattern numbers and the etched pattern numbers together as Walden made knives. I would not argue with your feeling that the ones with no pattern numbers are earlier than the ones with the pattern number etch. I have 2 Simmons Hardware Co. knives and 1 EC Simmons St Louis knife in good condition, with strong Keen Kutter blade etch, and no pattern number.
I have 14 KKs that I am reasonably sure are Walden made (based on the dates given by Sellens). Of these, 6 have a pattern number etch and 8 have none. Of the 8 with no pattern number etch, 4 are in good condition, with strong blade etch, and I assume never had a pattern number. None of what I consider my Walden made knives have a stamped pattern number.
I have 7 KKs that I am reasonably sure are Winchester made (again based on the dates given by in Sellens). All 7 have a stamped pattern number.
I have 21 KKs for which the dates, given by Sellens, span both sides of the 1922 to 1924 range for the changeover from Walden to Winchester (my most recently posted K2245 is one of these. Of these, 4 have no pattern number (older knives, pattern etch may have been worn off?), 5 have a pattern number etch, and 12 have a stamped pattern number. Winchester and Simmons merged (or Winchester bought Simmons?) in 1922, but the Walden Knife Co. was not dissolved until September 1923. I would assume that during the changeover, some knives continued to be made in the Walden facility even after Winchester became involved.
Back to the K2245, Sellens would date it to 1924 to 1929, based on the cocobolo handle and the crest shield) However, Simmons did not put out a catalog in 1923. There was a 1921/1922 catalog and a 1924 catalog. I am speculating (I am aware that it is probably a wild speculation), that my particular K2245 may have been made in the Walden facility in 1923 and first appeared (with the cocobolo handles and crest shield) in the 1924 catalog.
So to summarize: I believe that Walden made KKs have either no pattern number, or an etched pattern number. Winchester made KKs have a stamped pattern number. Camillus made KKs have a stamped pattern number which is preceded by a K. I know that this is based on a extremely small sample size. However, I study every KK, in good condition, listed on ebay or posted in this forum or other forums. I have been meaning for some time to create a data base of KKs from ebay (I do save photos from the ebay auctions for most of the good condition KKs) and the forums, but have not gotten around to it yet.
I do rely quite heavily on Sellens for dates for the various pattern numbers. He had access to every catalog Simmons put out, and, in my opinion, organized an excellent guide to the patterns. However, I do not consider Sellens to be an infallible guide. Simmons did not put out a catalog every year. There are numerous gaps of 3 to 4 consecutive years between catalog issues (1904 - 1908, 1908 - 1912, no 1916, no 1923, 1924 - 1927, 1927 - 1930, 1930 - 1935 and 1935 to 1939).
I believe that there are very likely variations of some of the patterns (handle material, shield types, coined liners etc) that were produced during the gaps in catalogs and did not make it into Sellens guide.
I would prefer to have access to all of the catalogs myself, however, the asking price for old Simmons catalogs puts them out of my price range. I have PDFs of part of the cutlery sections from the 1912 and 1917 catalogs, and also a reprint of the cutlery sections from the 1930 catalog.
Sorry for the long winded post. Please feel free to comment and criticize my "theory".