From https://i.imgur.com/H3IItkL.jpg
This image shows Wonsan had Chollima 82 trolleybuses at some point. My theory is that they underwent local body replacements to become the Songdowon trolleybus. Note that the front mask, apart from the windscreen are basically the same, and the wheel arches, with the flaps in between them are in the same location. The rear window on the Songdowon was clearly modified, since it has a very rough finish, as if it was changed later.