Including classification heads in BERT saves

Hi, I am using the Trainer with BERT for a classification Task. I saved the model with this command:

model = transformers.AutoModelForSequenceClassification.from_pretrained("bert-base-uncased")
...
trainer.train()
_ = trainer.save_model("history/")

Since BERT does not use a classification head, this code adds one, if I remember right. However, it appears that when I load this model after training with

config = transformers.AutoConfig.from_pretrained("history")
model = transformers.AutoModelForSequenceClassification.from_config(config)
tokenizer = transformers.AutoTokenizer.from_pretrained("learning/checkpoint-31500")
pipe = transformers.TextClassificationPipeline(
	model=model,
	tokenizer=tokenizer,
	return_all_scores=True)

It seems to create a new head again, not use the one it originally trained. This makes loading and using a trained model not possible.
How can I save the head that Trainer trained for bert within the model so I can load and use it again?

Thanks in advance!