Hey, new member here but I kinda have become a Mosin Superfreak over the last 6 months. I would not touch it, and definitely not apply some modern Shellac. From the limited pictures I see- you may have a true "matching number" non-refurb. The buttplate and barrel serials are complete and look like the correct matching fonts. If the bolt and mag look the same you have a real gem. Would be a shame to devalue it with restoration not preservation.