@OP:
Your rifle has indeed been sportered, as have so many millions of others.
You can see that.
You know that.
You don't need me to tell you that.
What you have is the remains of the Finest Battle Rifle Ever Produced.... and the capital letters are intentional.
You are lucky in that the Butt has not been Bubba'd, so that whole end of the rifle is fine. And you HAVE the rear upper handguard (which is called the LOWER handguard), so that is one less expensive part to try to find. You are correct in that the barrel has NOT been cut. It appears that your rifle still has the critical Inner Band, Washer, Spring and Screw which are necessary to make the rifle perform as it should. Your rifle is a perfect candidate for restoration.
To restore this rifle you will need:
Rear Sight Protector and Screw (2parts)
Middle (Barrel) Band, screw, sling swivel (3 parts)
Nose Cap (Bayonet Stud and Bar are integral parts with this), its Cross Screw and Screw, the Stud and Spring which bear upward against the barrel (5 more parts)
Upper Handguard
Fore-stock.
These last two are the hard ones to source. Trade-Ex has most of the others, as do half the people on this forum.
As well, there are extras which you WILL want: Bayonet, Scabbard, Frog, Sling, Buttstock Oiler, Pull-through, Wire Gauze, a Bandolier and a handful of Chargers. Forget about spare Magazines; such were never issued and, in fact, it is MUCH faster to reload the rifle with Chargers. Prices on these vary a lot. Generally, a Bayonet with Scabbard and Frog will run the thick end of 100 bucks, Sling perhaps 10, Oiler $5 to $20, depending on if you want Plastic, Bakelite, Steel or Brass, Pull-through maybe $5, Chargers perhaps a buck each, Bandolier likely $5. Trade-Ex has a lot of these things and you can find them in the PARTS section of "Military Surplus Rifles" on the Equipment Exchange.
And you will definitely want a MANUAL. This you can download from the Military Knowledge Library over at milsurps dot om. Click on the STICKIE at the top of the Index to this Forum and it takes you right there.
If you want to restore the old girl, get the parts and then come back on here. There is MORE to it than just slapping the parts on in the right place. That's the bad part. The good part is that it was all worked out very nicely a century ago and there are folks here who will walk you through a restoration.
In the end, you are likely to have a 100-year-old rifle which can down a Moose with 1 round...... or group all of its bullets on a smoke pack at 100 yards, given that you can hold her.
Worth going for?
I think so, anyway.
Hope this helps.
.