When I checked the collections for Black Lion stuff I noticed that these 3 Skins were unlocked in their collections altough I NEVER bought these skins or unlocked them on my account.
http://wiki.guildwars2.com/wiki/Lovestruck_Short_Bow_Skin
http://wiki.guildwars2.com/wiki/Tormented_Dagger_Skin
http://wiki.guildwars2.com/wiki/Tormented_Staff_Skin
The only other collection is see in the Black Lion Collections tab is the “Dragons Jade” collection where it shows the correct weapons I DO have unlocked: Greatsword, Axe and Sword. The only other Black Lion skin I have unlocked on my account is the “Bloody Prince Staff” so I have no idea why it shows the 3 skins I linked above as unlocked.