I used a label maker to make a decal of the "Police" lettering on the Gunkei Zaku. Others have explained in detail how to make decals with a label maker, so if you're interested, please search for it (at your own risk).
This time, I used a simple paint job. I preferred the blue of the main body to be a little darker, so I overcoated it with deep clear blue. I drilled a 2.5mm hole for the monoeye, attached the included sticker, and inserted a clear lens from another manufacturer.

I made a "military and police decal" using a Tepra | 元ボンボンSD名人S's Gunpla works