We use SCCM 2012 and SCUP 2011 to deploy our Flash ActiveX and Plugin updates using the catalog Adobe provides. (thanks Adobe for this!). I wonder if there is a Catalog for the Firefox plugin, NPAPI?
The Flash Player SCUP catalog includes both ActiveX and NPAPI plugin. If you currently license Flash Player you should have received an email with the link to the download page. If you don't currently license Flash Player, you'll need to license it for distribution within your organization. Please see Adobe Flash Player Distribution | Adobe to apply for a license. You'll then receive an email with a URL to go to to download the catalog.