This is pretty amazing, but still not conclusive because there may be unknown natural INORGANIC chemical processes that could create it. Labs create it by inorganic means all the time but it has never been observed to occur that way in nature.

Also, a single spectrograph reading is not irrefutably reliable. 

If they see a very specific isotope of organic chlorophyll consistently in a spectrographic observation like this, that would be damn conclusive. It's a very delicate molecule that is nigh impossible to make in the lab inorganically - relates to plant photosynthesis (the way plants convert sunlight to food).