I have noticed some MN rifles have metal sling swivels. Were these factory original to the Russian rifles, added in the field, or have other origins? I know the Finns sometimes used them as well as Spain. When I'm on an auction site for example, I have seen varied types, although few MNs with these. What does a rifles inclusion, or lack of sling swivels tell me about the rifle? The one I saw today didn't tell me anything really, because the pictures were kind of bad and there were not really any close ups. Its ongoing so I can't post it under the rules, but I am curious about it.