In Notes,it is possible that there are two mail template (ntf) files with different filenames but have the same template name.Since nsf files are created from an ntf file,how will we know which physical ntf file is being inheritted by an NSF if it we will refer “template” name only?
Subject: Not possible, AFAIK
You have to go beat up your administrator who allowed two templates with the same name, or the developer that created a duplicate with the same name. 
The only way you potentially could tell which template is if you use a versioning system for yourtemplates. I built one myself, using a shared field called $TemplateBuild to store the version number and build of my templates.
But out of the box, I don’t think you can do that easily.