By most people's reckconning, this is the 2nd Western Bowie, from around 1965 to 1966. The first ones allegedly came out in 1964 and had the word "BOWIE" on the pile side, inverted ( letters upside down when the knife is held tip up).
By MY reckconning, it is the 4th version.
The first version is a rare, very early 1928-1930 (IMHO) version with cracked ice handles and finger grooves.
The second version is the Bx54 Bushman, produced during WW2 as part of the AAC survival packs, similar to the Collins #18 little machete and the Case XX Army contract clone of the #18. Western's Bx54 had a small, steel, oval guard as opposed to the large brass guard with quillons.
The 3rd version would be what most people call the 1st version (as described above).
I currently have identified 18 versions of "49" Bowies similar to yours, up through the Coleman era to the Camillus era. This list does NOT include "other" Western Bowies, such as the 46-8, 38, 39, 43, 44, 45, 47 or 55. I'm working on a "Western W49 Family Identification" thread, but my camera is screwed up and I need to buy a new one so I can finish it.