Jenkins: deploying war files from artifactory
I don't know about a plugin which takes a version # and deploys that, but you can build a Jenkins job to deploy the last successful release to a previous environment (thus copying from DEV-->QA for example.)
To do this, you would use the copy-artifact-plugin.
Here's an easy to follow run-through of this kind of setup:
http://www.lordofthejars.com/2012/09/deploying-jee-artifacts-with-jenkins.html
Every artifact stored in Artifactory will have a unique URL that includes the version number. It will take the format
http://artifactory-server/repository-name/path-to-artifact/version/filenamee.g.
http://artifactory/apps-releases-local/com/yourorg/yourapp/1.5.67/webapp.war(depending on how you do your packaging, the WAR file name may include the version number as well).
So your deployment job can construct the Artifactory URL and download the file. Depending on how you have security set up in Artifactory, you may need to authenticate the request.