Unopened Aged Armagnac Cuvee Bernard VII

This bottle has been in the family for 40 years now and it was already an aged armagnac at the time. There is a lot number under the bottle "Q7L". I've recently stumbled on an identical bottle appraised at about 300 000 euro in value and the lot number under it was to my understanding more recent than this one. Can anyone please appraise my bottle for me.

Thank you in advance,

Costa