There was a time when such actions, complete, barreled, or stripped were readily available from a lot of sources. Back in the late sixties, I went with Mr Lever through the International Firearms warehouse facility in Montreal. At that time, you could pick up new in wrap 98 Mausers, complete with matching bayos, slings, cleaning kits for $10 each, if you bought a full pallet. Each pallet had 60 crates of eight rifles each. Sounds cheap and it was but Mr Lever had to ship them to Vancouver, uncrate and clean some of them (my job) for the racks in the showroom etc. Those rifles were sold to the public for $25 each.
Then, there were the rifles that had seen service/been issued. Mr Lever's cost on those was under $10 per rifle, delivered to his store. They were in every condition from Fair to Excellent, with most of them being Very Good at least.
Over on one side of the warehouse, there were a half dozen fellows breaking down firearms into their individual components. There were thousands of them being broken down. All of them were issued, used, abused and put away filthy. Most had a patina of light rust on them, from poor storage conditions. None of them were floated on grease, many had broken stocks or some other damage that put them out of action. About half of them were missing bolts or other parts.
The first thing one of the armorers/laborers would do is look down the bore and if necessary push a patched jag through it to check the condition of the bore. If the bores were Very Good or better, the barrel stayed on the actions. About 20% of the barreled receivers were matching and complete. Just needed stocks etc. These had special racks designed to hold them.
Then there was another rack of stripped but barreled receivers and the list went down to bins of complete receivers with trigger guards, triggers, mag wells, bolts. There was a bin for matching and a mixmaster bin.
A lot of the rifles in their racks had the bolts pulled and had been crushed across the mag well area. They usually stripped whatever usable parts were on them and sorted them into bins.
I was under the impression that the people stripping down these firearms were getting paid by the piece, rather than by the clock. They weren't particularly careful when they broke the rifles down. However, they were obviously getting a premium rate for complete and even mismatched actions. They actually used go/nogo gauges when fitting mismatched bolts to otherwise complete barreled receivers.
That being said, they were none to careful about turning the barrels off the receivers. I was shocked to see them clamp a receiver into the bare steel jaws of a vice to hold it while turning out the barrel. They had the proper tools for the job, such as barrel vices and action wrenches or action spuds. They weren't the least bit worried about using a three foot (one meter) pipe wrench to grasp the scrap barrell. They hardly even bothered to strip the rear sight bases or sights off the scrap barrels before tossing them into a scrap metal bin.
OP, given the appx time frame that the original owner may have acquired that receiver, those vice marks wouldn't be out of the norm. Not only that, most of those actions were picked up by the numerous mail order firearms marketing facilities in the US/Canada. Some even went back to the UK, where they either ground off or milled off the markings from the tops of the receivers, so they weren't concerned about the marks. All of this stuff was recognized as junk in its present condition. Still, lots of folks back then turned a lot of them into some very impressive hunting rifles.
OP, IMHO, by the time you get that rifle put back to its former state, it will cost you as much as picking one up in better condition, assembled at the factory.