AR Coating on an Optical Window

[microb]

If I have an optical window that might be BK7 glass or absorbing KG1 or KG5 glass, would any of these ever have an AR coating?

If I had the piece of glass in hand, how do I confirm whether it does or does not have a coating? Sometime it seems like an AR coating is pretty obvious. But is that always true.

I want to do a transmission graph on what is probably an optical window for dust protection on the path the the eye pieces. If it was for a lamp, they wouldn't do an AR coating, because basically why? But since this is on the path to the camera, maybe there is a coating. I don't know.

Thanks.

I'll take my answer off the air -- oh wait, that's call in radio. nvm...

[MicroBob]

If you put the window on a slide and hold both in an angle the reflecting properties will be the same in the window is uncoated.

[apochronaut]

In my experience, the coating is readily observable using a fairly short wavelength light source.