I think not. The turrets on T-26 M1931 don't have that little "slope" between turret side and top.
Finns had a great variety of different weapons and I think these rare submachine guns are quite interesting:
Finnish Suomi M/26 and American Thompson M1928A1. Suomi M/26 was a predecessor of Suomi M/31 and only 100 were made. Finns captured a small number of Thompsons from Soviets, especially in the Battle of Ilomantsi, where Soviet 3rd, 69th and 70th Naval Infantry Brigades wielded them.
SIG Model 1920 "Bergmann" and MP 28-II "Schmeisser". M/20 "Bergmann" was a licensed copy of German MP 18 made in Swiss and instead of 32 round magazines, it used ones with 50 rounds. Finnish Civil Guard (Suojeluskunta) bought around 1500 Bergmanns before Winter War and when the war started, these guns were transferred to Finnish Army. During the Winter War Finnish Army bought 171 pieces of MP 28-II from Belgium, but those arrived after the war had already ended. In the Continuation War those MP 28-II smgs were used by Finnish troops in Lapland, where some German units also used same guns.
Soviet PPD-34/38, PPSh-41 and American Thompson M1928A1. PPD-34 was a "first-generation" submachine gun based on MP 28, shooting bullets from a 25 round arch-shaped magazine. Later Soviets introduced a little bit improved PPD-34/38, which also accepted a drum magazine, copied from the Finnish Suomi M/31.
German VMP 1930 and EMP 35. Both were commercial weapons, but their development was secretly funded by The Reichswehr. I don't know how these weapons made their way to Finland, but I suspect the Finnish Volunteer Battalion of the Waffen-SS brought them to Finland.