I like making parts compatible in a manufacturer's line. Some of the parts you see here also made their way to the Karkpanzers, and all really have their origin in the Neo-Soviet Red Banner tank I did for Khurasan. More on that later...
The grenade racks are the identical bits used from the Karkpanzers, and can be mounted at 90 or 45 degrees.
Of course, "Modularity" being my watchword, you had to know that the turret socket looked awfully familiar in proportion...
Yup, part of the modernization of the Brick Tank and Brick APC entailed making them cross-compatible with the Red Banner series, which I had just completed at the time.
I'm pretty pleased with myself on making it work.
More to come later.
Edit: Jon gave some guidance, and let me know the difference between the designations as they pertain to his labeling.