Article before 'label'

I need to ask this question (note; I am mentioning the 'label' for the first time):

'The label on the back of her shirt said ...'

'A label on the back of her shirt said ...'

Could you please confirm that either is natural in this example? 'A label' sounds OK, I am introducing it for the time. But 'the label' also can suggest that there's only 1 label on the back of the shirt. Correct?