Anyone ever seen A Finn like this?

I had a metallurgist friend look at these photos. He's spent years forging and treating metals and says the "Dredged up" story is total BS. He pointed out that there are only two "layers" visible in the metal, and said that seawater and brine wouldn't leave marks that shallow. He showed an example of what the metal *would* look like, an old chain he pulled out of some beach. He also says that the metal's looking like that is most consistant with someone quickly dunking the rifle in some sort of acid, just for a moment before pulling it out. If he's right (and I have no reason to doubt him), there's much more to this mystery. It's a longshot and a bit dramatic but maybe the story of sunken ships was just a lie used to sell acid-dunked rifles to the unwary? If so it'd be a serious operation I suspect, not unlike that auctioneer selling "U-Boat ignition keys" years ago. Improbable? Yes. Impossible? No.

Is that also the Sako logo as well?