Generally yes, but you would have to create instances of these layers or use the functional API in your forward method:
def forward(self,x):
    out = self.layer1(x)
    out = self.layer2(out)
    out = self.layer3(out)
    out = self.layer4(out)
    out = Flatten()(out)
    out = nn.ReLU()(self.hidden(out))
    out = self.drop(out)
    out = self.dense1(out)
    out = self.dense2(out)
    out = nn.ReLU()(self.fc1(out))
    out = self.fc(out)
    return out