Nigel Harper
I've seen some reviews of this kit and there is no info re the decals. After some searching I located instructions for Express Mask ref number XT048 by Eduard. It goes some way to explaining the markings and therefore the decals. Also Osprey publishing have a title "BT Fast Tank. The Red Army's Cavalry Tank." ISBN 978-1-4728-1065-6. This clarifies how the markings were used and the decals included cover quite a few options so most wouldn't be needed.

EnsignExpendabl
Aleksei Rudakov goes over the marking options here and lists if they're appropriate or not:

3 red waves: yes
White stripe: yes
White stripe, black dashed line, number 12: no
White cross on the roof: yes
Rings: yes
Circle: yes (November 7th parade)
X-16: yes (also needs a white circle on the turret roof). There were also X-9 and X-61 tanks, so you can alter the decal pretty easily.

The article also goes over all the modifications needed to make the kit accurate, but those are harder to translate.