Other than the cinematic evidence I have not seen any documentation on the White Russians being supplied with scoped rifles; but I find it hard to believe that the Soviets would resort to providing a film producer with a dummied-up scoped M91/30 when foreign scoped rifles were readily available. The Soviets certainly had machinists who could make mounts or prop makers who could fabricate a prop mount & scope (and glue it on) for non close-up views. If prototypes were being developed at th time of the filming, it is unlikely that the Soviets would allow it to be have a cinematic debut. Second, would the Soviets spend time and money to make German style mounts for a foreign rifle? Limited resources in the Soviet Union mandates that any skills would have been used to develop mount prototypes for a M91/30 and besides, they had German mounts that could have reverse engineered. I'm certain those scoped Ross rifles were real. 1931 predated the unsuccessful Soviet primsatic PT scope's debut and before the PE was developed. In the typical Soviet pechant for secrecy, use the Ross and keep any potential foe in the dark about Soviet sniper rifle development.
Ross rifles were very accurate, but why send a SMLE with scope when the jam prone (when dirty) Ross would do? I doubt if the Canadian War Ministry would allow top line SMLEs to go to Russia instead of the Ross. Recall that Canada like the US supported the White Russians. I already mentioned the other German equipment and mounts the Soviets bought before Timoshenko's film, but it is highly unlikely that the secretive NKVD would share with a film production.
By 1942, there is no need for Gen. Morozoff to be deceptive about sniping. The Soviets were already making grandiose & unsubstantiated claims of one shot, one dead nazi and bragging how effective their snipers were. They asserted that a sniper killed "Field Marshal" von Kleist in 1942 (never mind that von Kleist wasn't a field marshal yet & he died post-war in Soviet capivity). Also in 1942 two snipers and political organizer Nikolai Krasvachenko were sent to represent the oviet Union at the International Student Conference. One sniper was Lt. Vladimir Pchelintsev (156 kills) and the other was Jr. Lt. Lyudmila Pavlichenko (309 kills).
There is one scene in that film that puzzles me. Check out the P14 at 11:20. Scope seems offset and what is that band behind the distance dial? Prop? Your thoughts please?