Hi Albert thanks for your input. I think that's where this one stands out-it's the correct size, weight, strike etc and hasn't been ‚washed' like the Canada 1948 silver dollars struck in Lebanon or some of the military medals I've seen to hide the poor strike or signs of casting. This one stands out in that I only put it through the xrf because I was there anyway and had found all sorts of fun compositions in other coins I'd scanned.
This points to what I suspect (but can't prove) as being struck with original dies if not original equipment. Does that make it a fake? An unauthorized restrike? Perhaps a trial run when they were seeing how the dies would strike the admittedly fussy design back in the early 1900s?
It's impossible to be certain. I will try and source another 1913 and xrf it as well and compare to the .950 example. Also may try and source a regular rouble and see what the metal contains.