My understanding is that the original V-42 knifes were manufactured by the W. R. Case & Sons Cutlery Co., Based on design by (then) Col. Robert T. Fredrick and Dermont M. O'Neill specifically as a SPECIALIZED FIGHTING KNIFE for O'Neill's Hand-to-Hand style of close combat taught to the First Special Service Force. V-42 design is a variant on Fairbairn-Sykes type fighting knife. "V" may stand for Victory or "Variant" and 42 is probably the year of design/acceptance.
Approximately 3500 to 4500 knifes were originally made by CASE with 3500 +/- going to The Force and some 500 +/- were supplied to MARINE RAIDERS in the Pacific Theatre were Marine Raiders were already using other Fairbairn-Sykes type variants.
Both Knifes were essentially identical including the "skull-crushed pommel" and "Thumb-print" grip, but the 1stSSF knife came with a long sheath so handle of knife was at mid-thigh for an easy draw level. Marine raider v-42's were issued with a shorter belt level sheath structurally identical to the 1stSSF sheath except SHORTER so knife handle is at belt level. Many FORCEMAN modified their early issue sheaths with copper reinforcing at the tip area for their own safety, it appears that the marine raider knive sheaths (and later 1stSSF sheaths)were all manufactured with the copper/brass reinforcing the tip area. THESE KNIVES WERE SHARP! The brass rivets were necessary to keep edge fron cutting through seam.
There are lots of WEB PAGES that claim to have info on V-42's, Wikipedia has good info.
WEB search DERMONT O'NEILL for info on a real colorfull character and his reputed abilities as a Martial Artist/Fighter.
My uncle, Robert G. Essig was one of the FORCE Chaplain's. I saw a V-42 in his Parish office in San Jose CAlIF. around 1960 or so. I don't know if it was issued to him or just given to him by another Forceman, but YES the V-42 does leave an impression on the mind.