Thank you for the response. Here is what I did:
my_list = ['classifier.3.weight', 'classifier.3.bias']
params = list(filter(lambda kv: kv[0] in my_list, vgg16.named_parameters()))
base_params = list(filter(lambda kv: kv[0] not in my_list, vgg16.named_parameters()))

And then defined the optimizer:
optimizer = SGD([{'params': base_params}, {'params': params, 'lr': '1e-4'}], lr=3e-6, momentum=0.9)

However, I get the following error:
TypeError: optimizer can only optimize Tensors, but one of the params is tuple

I get the same error when I try this as well:
optimizer = SGD([{'params': base_params, 'lr': 3e-6, 'momentum': 0.9 }, {'params': params, 'lr': 1e-4, 'momentum': 0.9}])

I am not entirely sure what I need to change. Any ideas?