You can reach the tank without much difficulty: a slightly rough road leads from the park to it, there will be 2 warning signs along the way :) border guards met us at the tank and took the documents for verification. They were friendly and polite. After a couple of minutes, we were already free :)
You don't need to go to this tank, border guards with machine guns will stop there and ask for documents. The border zone begins there. You can also get a fine.