I did more digging on another boared, and apparently sako and vkt (later valmet) made factory sporters in quite a few different 7.62x54 based rounds
6.3x53, 7x53r, 8.2x53r 9.3x54r, 6.5x54r, and 7x54
Also the other post says there was quite the industry of gunsmiths making one off's, which depending on the workmanship could be nicer then the factory rifles, if I was near the rifle the op is talking about I would take a closer look at it, it could be a really neat conversion, possibly factory.
Oh And that Olympic rifle is somthing else
And on another note, a lot of you older gentleman really lucked out, to be alive and around in the 50's and 60's (or closer to it) when a lot of gun smiths were turning there trade and pushing out affordable conversions of mausers enfields arisakas and others would have been an interesting time, sure the sporting rifles are cheaper to buy now to an extent, but we've lost some of the workmanship and character that went into some of these custom rifles, the cost to do some of the work put into these things now just makes people go buy another cookie cutter rifle punched out on machines with computers at the lowest overhead possible, yes some were "bubba'd" but others were fine examples of the trade
Back in those days and a few decades later, there were all sorts of cottage factories, producing after market products for the rifles you mention, all over the free world.
Herter's, Ackley Machine, Sherwood International to name a few. Some, like Numrich and others are still alive and doing well.
You could purchase a surplus 98 action, that had the top surfaces machined, drilled and tapped for scope bases and even engraved. There weren't any credit cards and phone calls were prohibitively expensive, if you had a phone, so snail mail was how business was done.
Sherwood had a deal where you could purchase a package, which included a complete 98 barreled action, aftermarket trigger, Douglas match grade barrel fitted properly, commercial grade walnut stock, fitted with a butt pad and 95% inletted for US$100, shipped to your door in Canada. The only fly in the ointment was that it takes as long to finish that last 5% as it does to get it to the 95% stage.
They were good deals in a lot of ways. Most people didn't have the proper tools to sporterize a surplus action in a manner that came anywhere near a commercial sporting grade rifle. Even then, often the people that purchased those kits had zero woodworking or metal working skills. The barreled actions were mostly in the white and needed to be sandblasted, polished, blued. The stocks needed final inletting, sanding and finishing. Some of the end results were beautifully engraved and matched or exceeded anything the commercial producers were offering. Others were so bad they were relegated to dark closets or just thrown out.
One other thing, if you wanted iron sights, tangent type or dioptic the receivers/barrels were drilled and tapped for the type ordered, at a cost of course.
In the fifties and early sixties, scopes were not readily available and for most, unafordable. Not only that, most commercial scopes from that era weren't as good as the cheap, low quality scopes available now. I remember all sorts of strange mounts and scopes. Those little square, surplus German sniper scopes were seen occasionally as were the surplus Lymans and No 32s, or 3/4 inch tubed Weavers. Once in a while other surplus European scopes could be seen, tragically stripped from souvenir snipers or sporters collected during the war. International Firearms used to offer all sorts of milsurp rifle scopes.
Those were heady times. People were much more self sufficient, practical and politically aware. Their personal privacy and individualism were held in high regard. There were other things that were blatantly rampant, such as outrageous racism, homophobia.
You could purchase and own anything, other than full autos and handguns, without special licensing. There was a local gas/mechanics station about 10 kliks from me, that had several full auto rifles and machine pistols for sale and hanging off the rear wall of the station. They didn't even bother to lock them up after closing. Things were much different then. Some things were better but not all by any means.