Are you the one saving the state_dict? If so, you could do something like this:
torch.save({
            'model_state_dict': model.state_dict(),
            'drop_rate': drop_rate
            }, PATH)

Then load it as:
checkpoint = torch.load(PATH)
drop_rate = checkpoint['drop_rate']

model = theModelClass(drop_rate)
model.load_state_dict(checkpoint['model_state_dict'])