That’s definitely their uniform but I’m wondering if it’s just a coincidence. Opolchenie would have been an infinitely better name than Northern Musketeer so it’s odd they wouldn’t go with that if they were aware.
I did come across Opolchenie while researching alternatives, but I wanted to go for something with a stronger connection to royalty. With Lieb Guard, you could also have a new Toy Army card that ships them and buffs all of Russia’s weak infantry.
I also wanted to shift the strong musketeer unit to Oldenburg, and give Habsburgs a weaker musketeer (Grenzer) instead. That way there wouldn’t be so much overlap with both Bourbons and Habsburgs having strong musketeers and appearing on the same maps.