Solved by ptrblck in post #2 
              
              
                How did you save the state_dict and what keys are inside it? 
Saving and loading the state_dict using your model, works fine: 
torch_model = models.vgg16(pretrained=False)

torch_model.classifier[6] = nn.Sequential(
    nn.Linear(in_features=4096,
        out_features=1, bias=True),
    nn.ReLU(),
 …