Moonlight development was stopped before the release of Silverlight 5.
Silverlight 5 was the first version with 3D graphics support.

Moonlight never really worked for me on desktop linux, also the Silverlight version for Symbian S60v5 never got out of beta state, and is useless imho because of bugs and lack of compatibility.

So I think the anser is: No, silverlight application can't be run on Harmattan