This one is bit of a general topic. Do we have to sign a plug-in for it to work in Mountain Lion.
Gatekeeper provides three potential levels of protection:
1. Applications can be installed with total freedom.
2. Applications can only be installed if they are signed with an Apple Developer ID or if they come from the Apple MacOS App Store. This is the default option.
3. Applications can only be installed if they come from the Apple MacOS App Store.
I know to be on the safer side we need to sign the plug-in but, so far I haven't seen any issues while testing the plug-in on Mountain Lion.
Any Updates/Info on this is welcome.