Contact Vintage Grips and tell them of your dilemma. Since they are always looking for pattern grips, they used to offer a free set of grips in trade for using the original grips as a pattern.
Many people fought in the war. Many people owned firearms. Just because Gramps owned a pistol and fought in the war does not mean the two are related in any way. Wars are fought with military weapons, not pocket pistols.
Never try to educate someone who resists knowledge at all costs.
But what do I know?