Guild Wars 2

I purchased the ascended light armor craft recipe for the Wei Qi’s Sentinal Coat, and I see now I need the Wei Qi’s Sentinel Insignia. Can you please tell me how to get that? I do not see a recipe available for purchase on the Trading Post nor in game from the vendors.

If a recipe for a finished item is available then I thought that the insignia recipe would be available some where.

I read in the forums of a dungeon with Sentinel recipe drops at the end but that appears to no longer be in the game. Will we be able to get any Sentinel recipes and specifically the “Wei Qi’s Sentinel Insignia?” This is such a specific insignia that I don’t believe I can even buy a Sentinel Item and get that specific insignia extracted from it.
Thank you.

As far as I know sentinel inscriptions are available for guild commendations trough the guild vendor.