Ukraine

Did some quick reading and the Mi-8t can have a few goodies. Either front or side mounted guns as well as rocket pods. There are about a dozen or more variants of the Mi-8 but I would speculate that the underlying frame is what matters.

From my experience with other military helicopters (not Russian ones), helicopters are fairly "modular". The mounting points for guns may still be on the frame, but windows can be easily swapped out (or simply opened) when needed.

A good visual on that "modularity" is the difference between a Blackhawk and a Seahawk and the position of the rear strut. Same frame, completely different positions of the wheels. (Having been inside the tails of a few Seahawks, I can tell you the framing is still there, it's just lacking everything else.)

Edit: "modular" is in quotes because even if there is a common frame, it can still take quite a bit of work to make some types of changes. If I am not mistaken, and using my previous example, the Seahawks still have an access port with a blank panel instead of the full rear strut of a Blackhawk. You would still need to modify the tail significantly to change the strut position but it could be done during a maintenance rotation. (A D-phase service, if I remember correctly. The bird would be stripped down to the frame anyway.)