diff --git a/lib/templates.php b/lib/templates.php
index d99d146e9eff4..903cdb7093b2b 100644
--- a/lib/templates.php
+++ b/lib/templates.php
@@ -374,6 +374,20 @@ function filter_rest_prepare_add_wp_theme_slug_and_file_based( $response ) {
 			$file_based                   = in_array( '_wp_file_based', $wp_theme_slugs, true );
 			$response->data['file_based'] = $file_based;
 
+			$response->data['original_file_exists'] = false;
+			$template_files = array_unique(
+				array_merge(
+					_gutenberg_get_template_paths( get_stylesheet_directory() . DIRECTORY_SEPARATOR . 'block-templates' ),
+					_gutenberg_get_template_paths( get_template_directory() . DIRECTORY_SEPARATOR . 'block-templates' )
+				)
+			);
+			foreach( $template_files as $template_file ) {
+				if ( basename( $template_file, '.html' ) === $response->data['slug'] ) {
+					$response->data['original_file_exists'] = true;
+					break;
+				}
+			}
+
 			$theme_slug = array_values(
 				array_filter(
 					$wp_theme_slugs,
diff --git a/packages/edit-site/src/utils/is-template-revertable.js b/packages/edit-site/src/utils/is-template-revertable.js
index 4bb8c6f6e27e9..02c1c60cf2aab 100644
--- a/packages/edit-site/src/utils/is-template-revertable.js
+++ b/packages/edit-site/src/utils/is-template-revertable.js
@@ -13,6 +13,7 @@ export default function isTemplateRevertable( template, currentTheme ) {
 		'auto-draft' !== template.status &&
 		/* eslint-disable camelcase */
 		template?.file_based &&
+		template?.original_file_exists &&
 		currentTheme === template?.wp_theme_slug
 		/* eslint-enable camelcase */
 	);