Can I jump in?
1. Yes, it seems like there was only two pictures of T-26-4 published so far. These two photos were taken during the trials. The tank never went into production. Different sources are saying there was only 4 or 5 tanks build in total.
2. In theory, the turret can be scavenged from BT-7A. To be accurate, they are little different in size and in design, but I can bet that nobody will notice if you don't tell them. But even if you do tell them, they will not know the difference anyway.
3. The star on the roof is actually stamped (pressed) out. It was done to reinforce the flat metal sheet of a roof of the turret. Since they were bigger, the turrets of T-28 and T-35 also had two "lines" besides the star.
Let me know if you need additional info, but Mauro pretty much covered it all already.
Alex
P.S. Yes, for some reason ICM did not mold the star in their kit.
P.P.S. Yes, it does look like BT-7A did not have the star.
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