See which file WP is loading for templates

functions.php

// this can live in /themes/mytheme/functions.php, or maybe as a dev plugin?
function get_template_name () {
	foreach ( debug_backtrace() as $called_file ) {
		foreach ( $called_file as $index ) {
			if ( !is_array($index[0]) AND strstr($index[0],'/themes/') AND !strstr($index[0],'footer.php') ) {
				$template_file = $index[0] ;
			}
		}
	}
	$template_contents = file_get_contents($template_file) ;
	preg_match_all("(Template Name:(.*)\n)siU",$template_contents,$template_name);
	$template_name = trim($template_name[1][0]);
	if ( !$template_name ) { $template_name = '(default)' ; }
	$template_file = array_pop(explode('/themes/', basename($template_file)));
	return $template_file . ' > '. $template_name ;
}

header.php

<?php if ( ! is_admin() ) {
    echo ' | '. get_template_name();
    } else {
     echo "";
}?>