Gloss coatings can be measured using the Vates instrument.

The Vates can measure diffuse reflectance and gloss from different angles and it's high speed allows to perform a surface scan of the display.
The Vates is a compact solution which can be used for either in-line and off-line analysis of surfaces.
Additionally it can be used to measure the following items for (reflective) displays :

Colour Reflection Uniformity Contrast ratio Response time Flicker (if applicable) Gloss