French frigate

This is the Mont-Blanc in 1791, 74 gun ship, by Antoine Roux. Not frigate.

Do you know on which basis this 74-gun ship was identified as the "Mont-Blanc" and by whom? I tried to read the name of the ship on the stern but failed. The first time I have seen the name of "Mont-Blanc" attributed to this ship was in Christie's Maritime Art catalogue of Wednesday 29 October 2008, without proper reference. They just pointed out that the painting was published in a German exhibition catalogue of 2002, but there the name of the ship remains unmentioned. Actually, the painting was just signed and and dated "Ant[oin]e Roux a Marseille 1803 = 45 -".

BTW, isn't that a chef de division's pennant on top of the main mast? 

Edited October 28, 2018 by Wagram