Congratulations on acquisition of a latter Qing peidao, a general classification for the Chinese sabres. The Boxer Rebellion attribution is typically a well placed attribution as a great number of Chinese weapons returned with the forces of the eight power foreign legations there during these complicated events.
These patinated old weapons are fascinating, and I think restoration simply detracts from thier character personally. Obviously active corrosion should be checked, but taking the dark patination off will only reveal austere metal. The remnants of the japanning on the iron remains, indicating its intent for campaign use, and it seems wrong to remove that.
I am by no means well versed in Chinese weapons, but I feel that some context for this weapon is what you're looking for as well as I wanted to provide same for others interested in this field of study in arms. I have spent some time going through old notes and articles, much of which derive from years ago with Philip Tom and Scott Rodell, as well as from things I have learned from Gav more recently .
It is important to note that of 'Boxer Rebellion' swords, the most commonly seen are the 'oxtails' (referring to the blade). These 'neu wei dao' are actually civilian martial artist weapons. Yours corresponds to the 'liuyedao' or 'willow leaf' form blade. The mounts, scabbard and hilt are with latter Qing (end of 19th c.) traditional form known as 'yuan' or rounded. Earlier forms are 'fangshi' or 'squared'.
As I mentioned, the Boxer Rebellion and its period were turbulent in China and the forces of Empress Dowager Cixi were torn between ousting the foreign 'demons' and there were factions more moderate toward them.
The Empress, while wanting to assist the 'Boxers' in forcing out the foreigners also tried to carry forward diplomatic measures. Expectedly there were clashes between Imperial forces in these split factions.
This peidao seems, by its rather austere mounts in traditional form as well as the appearance of the liuyedao shape blade in the nature of the metal, could very well be an ersatz weapon used by the Imperial army or its auxiliaries. As noted, this is not a Boxer weapon. It is quite possible that it may be among weapons for the Kansu forces which were brought in from Gansu to assist as conditions escalated.
The character of the mounts in the simple hunshou (disc guard) and tiliang (suspension bar) as well as the scabbard chape seem to support this rather business like character as would have been found in supplying forces in such times.
My thoughts, and I would invite those who collect and study these Chinese weapons to add thier comments or of course corrections. I think these weapons deserve to have thier stories told, and that others will share that goal as well.
Nice going David!
All best regards,