Glossy Ibis near Florence, CO

I found this apparent Glossy Ibis earlier this week in a flock of about 90 White-faced Ibis feeding in a flooded field in Florence, CO. It appears to have the field marks for Glossy Ibis:  dark eye, light blue border (does not wrap around eye) to loral skin,

I had some concerns that the plumage does not have the iridescent purple green gloss field mark for Glossy per Sibley and Crossley in their field. In fact the plumage looks the same on this Glossy as well as the two White-faced Ibis next to it. I have been advised by two highly respected birders that "iridescence differences are unreliable". SeEtta