Judging by the quality of the work on the tank, I think that’s a safe assumption.
The gussets can be made out of paper. They’ll be close to scale thickness and you can add all the rivets you want very easily. You can use a gear from an old Tamiya motor, or even this:
I’ve done railroad bridges this way. I’ve still got one in the motorcycle/model storage facility, otherwise know as my garage. Properly painted and weathered, the wood/paper bridge looks like steel. In fact you can even use heave paper on the sheathing as the rivets can be added to that as well.