Once you have installed the plugin "Knowledge Management - Service Portal" you'll be able to make use of the same operations that are available with the Knowledge Management V3 plugin. The same is valid for versioning and refering to articles by its' number.
When using the widget "Knowledge Article Content" to load an article, the following URL structures may be used:
This will show the latest published version of the knowledge article
This will show the article version according to it's sys_id, however, in case it's not the most recent version, it displays a note like:
"An updated version of this article is available"
and link to it