Thanks for clarifying the use case!
There are some minor issues in the code.
You should store the state_dict, update it, and reload it afterwards:
    def __init__(...):
        ...
        w1 = self.conv1.weight.detach().numpy()
        print(w1[1][1][1])
        state = model_zoo.load_url(resnet50_url)
        state_dict = self.state_dict()
        for k, v in state.items():
            if 'fc' in k:
                continue
            state_dict.update({k: v})
        self.load_state_dict(state_dict)
        w2 = self.conv1.weight.detach().numpy()
        print(w2[1][1][1])
        w3 = state['conv1.weight'][1][1][1].detach().numpy()
        print(w3)