Yes, though the range is more limited than when using the sun, even after accounting for the much darker background. I've only tried it at very short range - about 100 yards. Trying this at longer ranges and videotaping the results is on my "to-do" list.

Per [1], moonlight was used operationally in Egypt ca. August 1881 using heliographs: "During this campaign it was used between Кassassin and Mahsameh for signaling with the light of the moon at its full."([1], p. 282). I make the range about 5.3 miles, if I'm correctly identifying "Кassassin and Mahsameh" with "Qassasin & Mahsama". I'm not sure what size mirrors were used - 5" diameter was the later British standard, but in the early days they used both larger and smaller mirrors.

[1] http://books.google.com/books?id=qmG1jUW-0E4C

Operations of the French Navy During the Recent War with Tunis
By Miers Fisher Wright, United States Office of Naval Intelligence
Translated by Miers Fisher Wright
Published by Govt. print off., 1885
page 282: