I can’t speak to the number of these but it stands to reason it would be very few. Wartime production was dedicated to main line combat rifles to the almost total exclusion of everything else. Any non-main line military arm and civilian arms from this period is a bit rare.
https://rangeleyflyshop.com/
My guess is these folks had them manufactured or had branded a manufacturers stock rod with their name at some point in time. It doesn't look like they carry private label rods at this time.
Bought one years ago, chopped about six inches off the barrel with a hacksaw, faced it with a file and chamfered the muzzle with a brass bolt chucked in a hand drill with valve grinding compound. Used to be able to keep three shots under an inch at 100 yds with iron sights when the eyes were...