This plugin provides a page templates dropdown on the post edit screen, where you can select a template of your choice to be applied to the post.
The post will render in the selected template view rather than the default single view. However, if ‘default’ has been selected from the dropdown of page templates, then the post shows up in the single view only.
It does what was promised. It shows a dropdown to choose from the available template files (same template options as for pages). Excellent!