...his father who's a retired Army colonel who served in the Korean war commanding tank battallions.
I would have friend ask his Dad the story behind the rifle in question first. How did he come by it, etc? It might be a DCM post war or it might be one a friend of his actually carried in the conflict with stories of it's own as Kraig suggested.
Depending on the tale, proceed. One course of action might be... Keep the original stock, with an alternate to buy a new stock set. Make the rifle perfect mechanically, but keep the character of the metal as is. Insert rifle action in new stock or if old stock was carried by friend, bring it up to current but worn condition.
I'd like to know the tale that rifle could tell (as it were), if any, before I proceeded on a total refurb.
WEB Griffin stories not-with-standing, few if any Tankers carried Garands (but a Unit Commander might have his own prerogative)... and while there might be a slight chance of one or two who did and if it saved their butt... ya know? A long stretch for sure, but strange things happen in wartime, or so I'm told.