I originally thought the blue hue from the pic in Ilia's quarters was from the lighting. But looking at other pictures makes me think it does actually have a slight bluish hue. Here are some other links where you can see the prop.
Screencaps of from after Ilia got digitized:
http://movies.trekcore.com/gallery/displayimage.php?album=594&pid=64044#top_display_media
http://movies.trekcore.com/gallery/displayimage.php?album=594&pid=64043#top_display_media
Tops Trading Card "The Phaser Battle"
https://images-na.ssl-images-amazon.com/images/I/61UnyAPxqSL._AC_SL1000_.jpg
The phaser definitely has a blue hue, but a much darker value than the blue-gray uniforms.