I guess I'm asking what it means that its sporterized?
It means it started out looking something like this:
Small variations depending on the country of origin, but it would have had a full stock, upper handguard, bayonet lug, and iron sights, and in all likelihood been made in 8mm Mauser.
Someone threw away everything but the action, and built that rifle.
Are there any markings on the other side of the rifle?