While you are on the site, in your browser find and click "Add to Home Screen" A CGN beaver app icon will then be created to your phone that is directly link to the site.
Note: This feature may not be available in some browsers.
Its a batch assembly number that was applied to the action and underside of the bolt when they were paired. Serial numbers came later during assembly.
You said your bolt is a match and therefore may have the same number on the underside, but it may not also. FTR'd rifles often had the bolt replaced and re serial numbered but this number was not re applied.