It is, however, I don't think you actually need to change anything. I assign the Facebook tags on our website (Since1910.com) to provide full link representation (images, video, etc..). You can see it in the headers here: Product View. If you view the source of that page, and review the headers. You will see the following header tags, each of which is written from OWS:
<link rel="canonical" href="http://www.since1910.com/tacori-2620rdp-halo-engagement-ring-with-pave-set-diamonds" />
<meta name="og:Title" content="Tacori Halo Engagement Ring w/ Pave Set Diamonds" />
<meta name="og:description" content="This stunning engagement ring setting is hand made by Tacori and features round brilliant pave-set diamonds around the center diamond as well as on the shoulders of the band." />
<meta name="og:image" content="http://www.since1910.com/images/products/tacori-halo-engagement-ring-with-pave-set-diamonds-2620rdp-1-C.png" />
<meta name="og:video" content="http://www.youtube.com/v/BmkhMoCuboc" />
<meta name="og:video:type" content="application/x-shockwave-flash" />
<meta name="og:video:width" content="800" />
<meta name="og:video:height" content="600" />
All of these tokens are working properly from Facebook.
The OWS is very straight forward here - simply use an Assignment action and set the Name to Page.Meta.METANAME. Then set the value to whatever goes in the content attribute. The tokens I am assigning are:
Is there a different reason why you need to create an additional plugin for this??