>>279906690
Tanks just have to follow 'real ' designs, there are no mentions of them having to be converted from real tanks. gekkan senshado or any disclosed japanese information didn't mention any of this.
Senshado is just like video games with tanks, and is already different from the real war. Even some tanks behave different compared to their real world counterpart like having higher top speed or turret traverse.
Some tanks like the Maus are just more expensive and harder to build because technical data and blue-prints are limited or missing. That means most parts have to be built from scratch from the beginning, and that requires custom build or making new plants for mass production.