Manifesto Dominations is not completely accurate with their units. For example, the Flammpanzer is based on A7V, which wasn't really a flamethrower, it was the first tank the Germans built. Similarly, HT MK4 is based on a Russian Zveroboy tank, which is a tank destroyer but it didn't start out as such. Its original intent was artillery with heavy armor, it just happened to be good at taking other tanks out. Also, even the description itself for heavy tanks says they fell out of favor after WW2 due to offering few advantages over regular tanks. As such, if the game intends to keep them, I'd expect the design to be based on regular tanks instead since we're unlikely to see functional examples of heavy tanks in later ages.
Freightshaker M60A2 may be it, it seems to have several variations for its turret but some of them do look similar. It even has that extra bump/hatch in the back, just that the one on M60A2 seems to be to the right instead of being perfectly centered like the Dominations version.