Vintage GD vinyl question

I am not sure if I should post here or Other Stuff section. However,I need help to identify 3 Grateful Dead vinyls from my late husband "Bart 's" vinyl collection.The labels are yellow,blue and pink.....all blank.They are in sleeves and in a black box. The only markings are very small etched GD-1,GD-2,GD-3,GD-4,GD-5 and GD-6.

I no longer have a turntable. Maybe I will have one of the Dead hour dj's at KVMR take them for a spin. 

Thought someone here may know.Thanks!