Will be in K2 v3 option to set K2 item alternate layout for each K2 item. Now we can set alternate layout only in K2 category and K2 menu item
Thnx
https://www.dropbox.com/s/2zckyuwazn1guke/altlayoutK2.jpg?dl=0

Unfortunately the template can be applied only to the category.
However you can build your custom template based on the item's id in your overrides.