That Gun Digest was 1963.

Seen one here in Oz in 358 Shot accurate, Not as accurate as the owner but then again he is a Natural..
Nice not heavy by my standards..
Luke in Oz

I have no idea where you would get a replacement stock but at one time MPI made a fiberglass stock for the standard 3 shot version. The guns were made with two different clips...one flush (3 Shot)and one that stuck down below (4 shot and these were the earlier ones made). The two calibers were 243 and 308 although there was a report of a 22/250. There was no 358 or whatever. Maybe someone re configured one along the way but nothing like that from the Sako factory. Matter of fact...Sako has never made a rifle in any manner chambered for that caliber.
There was a deluxe stock like the deluxe bolt rifle and that is one pictured on the cover of 1962 Gun Digest. I have seen it but I still think it most likely one of only a handful of deluxe stocks ever done in Finnwolf.
The first VL 63 (Finnwolf) was shipped 11-16 of 1959. Serial numbers 2 thru 219 were shipped from '62 thru '64.
In '68 the factory started with SN 1001 dnd the last number shipped was 12,500 on May of 1974.
The weakness if you wish to call it in the Finnwolf was the Hammer spring , spring guide and hammer spring rod....parts 513, 514 and 515 on the parts guide. In rapid action of the lever you could get the spring in a bind and then the rifle would not operate properly.
This was a very expensive firearm to make and that is one of the reasons it had a short life span. The factory museum also has a semi auto version of a Finnwolf but it was never put into production.
The first thing you learn in collecting is never to say never because you have no idea who took out what from the factory or who had a buddy at the factory that made up just that one for them. I had a one pc. Mannlicher stock Sako in my collection that was a Deluxe stock and I have seen one more. Even the factory said in a letter to me they never made that but....they did.

I have the following
Savage 99
Browning BLR
Winchester 88

All in .308Win I would love Finnwolf do you have a price on yours?
RLI