This is a good discussion to have.
AFAIAC,all the main parts must be original to that serial number. Stock, action, barrels, triggers, forend, trigger guard. Replacing or repairing the small parts within to restore function is OK to me. If you start replacing pieces to make a more modern firearm, you are modifying, not restoring.
Refurbishing barrels, steaming out stock dents, these things are an attempt to return to a "prior state". So I consider them OK.
But I come from the antique furniture side in all this. Original technique and materials count there.
