Question about 1792 Blandy ‘Napoleon’ Madeira sold at auction

[Le Gamin de Paris]

This week saw a huge price (£20k + 25% commission) for a bottle of 1792 Blandy Madeira! There is only a single photo of the bottle which you can find here: https://www.christies.com/lot/lot-6366965

It says that this famous Madeira was bottled in 1840. However, this bottle has a gold metal capsule which (I’m guessing) comes from the 1950/60s. Please correct me if I’m wrong. Other photos I’ve seen of this 1792 vintage didn’t have this type of capsule.

Does anyone have any opinions on the date of the gold capsule and how this legendary bottle could have a capsule added way after the supposed bottling date. Does this mean that Blandys held a stock of this famous Madeira until the mid-20th century?