There is not at all any aftermarket modifications, only adjusted trigger with wider fingerbar. Zeiss Victory 6-24x56 with illuminated reticle#43, Optilock ringmounts, Weaver Polarcaps and Harris pipod.
That is one beautiful rifle! Those little Sako actions are jewels! Also, the wood on your rifle is about the best I've seen on a Sako.
I have a Vixen in .223 that belonged to my uncle and I cherish it. My friend has two Sakos like yours, one in 22 PPC and one in 6PPC. Those are the most accurate off-the-shelf rifles I've ever seen (they even beat my Savage BVSS-S).
Once in a while even I speak Finnish. What are you using the SAKO for? Do you hunt grouse (teeri, metso) with it? Would be perfect for that task. I have a 6PPC benchrest gun, I can only imagine what a 22PPC would do taking down a few grouse from a distance. That is a sweet setup! I have a 3-12x56 Victory Diavari on my SAKO AIII (7RM) and I am hoping my next Varmint rig will have the same scope you're wearing on yours. Best (hunting) glass money can buy!