Howdy and welcome to Parallax Bill's!

As Davis pointed out, if you can find an original and complete stock set you can restore the rifle to original military condition.  Many collectors will forgive a mismatched stock because it is not that infrequent of an occurrence but it will still lessen the value somewhat.  Depending on the condition of the sporter, it is likely that it will have more value in military condition.  As a sporter, it is just an "old gun."  As a military rifle it is a collectible.  As such it might be worth something in the $300s.  As with any collectible item it's value is largely determined by condition and how badly any one individual really wants it.  We have all seen crazy auctions where a $200 gun has sold for over $1,000 (that's right, a comma and 3 zeros).   That's just craziness but, it happens.

As a reasonably well made, plain but serviceable sporter, it is worth $200-$300, maybe a little more tops I'd say, and most people aren't knocking down doors to get 8mm sporters either.  Unless you reload, your ammunition choices are limited. If it's a "bubba" a rifle that's been badly mauled by somebody obviously not a skilled gunsmith, you're looking at under $200.  Sporterizing has been called the art of turning a $400 gun into a $100 one and very often that's literally true.
A vet brought his rifle home from the wars was often a hunter who had a far greater interest in having a sporter instead of keeping an example of a weapon people had been trying to kill him with.  Then too, when they were coming in by the pallet full for under $100, sometimes under $50, making sporters was a logical step too. But these days, that equation has drastically changed.  There are no more pallet loads of these coming in and most military Mausers cost between $300 and $400+.  But unfortunately, many still haven't realized that yet.

Anyway. There you go and again, welcome to the forum!