Jacek,
I will be visiting here because wheeled vehicles are my favorite models.
I have built one Jelcz (
Jelcz 325 "Himalaya Expedition", 1:25) and I know that the cabin design in the whole Jelcz 300 series from Answer is a mess. It's about the front of the cabin. It won't look like it does on the cover. I have a revised design for this cabin. Corrections were made by pawelelka77 from the Kartonowki.pl forum. I made a few of my corrections around the windows and removed the color. If you want to, I will attach a PDF with the corrected cabin.
Pozdrawiam,
Sebastian