I use GO on everything. I find that on matte paper, it adds a but of scratch and scuff resistance. I have never had any problem with GO on gloss or luster paper but matte can be tricky. The issue seems that the printers require a certain translucency level and the combination of paper type, thickness and image can result in a translucently level below what is required. Thus, thick matte paper plus dark image equals no GO.
As a test, try printing a GO coat on a blank sheet of paper.