Your current code will only save the model.state_dict, i.e. all parameters of your model.
The model structure will not be saved, so you should always keep the model definition close to the checkpoint.
Also, if you would like to use this checkpoint for finetuning, I would recommend to store the optimizer.state_dict(), since some optimizers have internal parameters (e.g. Adam), which would be otherwise reset to their default values.
Have a look at the ImageNet example 121 to see, how the checkpoint is created.