Knives come in many shapes and sizes, but I noticed that the combat knife looks particularly similar to a KABAR that I own. So I started comparing images, particularly noticing the blade profile, fuller, ricasso, grip, and rounded pommel.
In game, Standard:
Also from KA-BAR:
All-black variant from A.G. Russell Knives:
Though I feel like I may have found the right knife, I have not as yet found any information to confirm or contradict my belief. Looking through the Fandom page for the Combat Knife, I did not learn any model details. The Wikipedia page doesn't say anything about Fallout, but does make an interesting note that corresponds with the timeline:
Ka-Bar is the contemporary popular name for the combat knife first adopted by the United States Marine Corps in November 1942 as the 1219C2 combat knife (later designated the USMC Mark 2 combat knife or Knife, Fighting Utility), and subsequently adopted by the United States Navy as the U.S. Navy utility knife, Mark 2.
Broadening my search, I tried to find articles that refer to knives generally in gaming, hoping I might find a new lead. So far, the articles I have found have not yielded any useful information (1, 2, 3, 4, 5).
Can anyone confirm or deny with a game file, Bethesda statement, or other authoritative source that the Combat Knife in Fallout 4 is a 1219C2 KA-BAR knife?