The BladeForums.com 2024 Traditional Knife is ready to order! See this thread for details:
https://www.bladeforums.com/threads/bladeforums-2024-traditional-knife.2003187/
Price is $300 $250 ea (shipped within CONUS). If you live outside the US, I will contact you after your order for extra shipping charges.
Order here: https://www.bladeforums.com/help/2024-traditional/ - Order as many as you like, we have plenty.
Just because he got it during the Korean War does not mean it would not have been GI. When WW2 ended, the Navy and Marines had enough to last until 1960 before needing to order more. "Theater" knives, those modified after being issued by some one "in the field". have been being made since the first soldier was issued a knife even back in the Bronze Age. Your father's was not modded in the field, per se, on the front lines or in a camp, but by an REMF that had access to a machine shop, either at a base or on a Navy ship. The plastic used frequently came from aircraft cock pits, truck tail lights, miscellaneous GI components that had extra plastic stuff that wasn't being used at the time. Any aluminum used could have come from aircraft skins, scrap metal or machine shop stock. Brass, when used, sometimes came from shell casings, scrap, etc.
It would most likely be a 1 off mod, unless the modder did several at one time. If it was done as a "presentation" knife for whatever reason, a singleton would make more sense, except if the "presentation" reason was for multiple individuals for doing the same thing, whatever the "thing" was. Someone took a lot of time to make that one, making sure the plastic and metal discs of the handle match up well. It also looks like it has a pommel nut. The modder might have threaded the tang to hold every thing together with a nut, or it could just be peened back together. Is the pommel peened or does it have a threaded nut?
Take a look at the various "commemorative" 1219C2s/USN-MK2s Kabar has made over the last 20 years. They are all made just like the original (well, almost - they have pinned thick pommels, which were NEVER made during WW2 - one of the ways Kabar makes them so they can't be claimed to be real WW2 knives).