The thumb cut does not necessarily identify the rifle as military. I have a Husquarvarna made Swedish Model 46 Mauser in 8mm that was made as a sporter but still wears the thumb cut. The thumb cut only became superfluous when the rifle was scoped but for open sight use and quick reloading, the thumb cut is perfectly functional and very useful.
Also, after the war there were many, many (probably thousands) of M98 actions laying around and regardless of where produced wear the thumb cut. I have no doubt the post war sporter makers used tons of those actions. Hey, even my Swede, which was a used but beautiful European style sporter when I got it, is still nothing more than a Swedish made M98. This darn thing still had a 2 stage military trigger and the stepped barrel when I bought it. Now it carries a Bold Trigger with integral safety, smooth bolt block, and a scope but before that it was just a pretty M98. Mikey.