I think you misunderstand the changes brought about by 41F. There is no longer a CLEO CERTIFICATION, it is now just a NOTIFICATION. There is nothing for them to sign anymore, you just certify that you sent them a copy of the form on the ATF form 1/4. Many of the CLEO's do not yet know this, although BATFE sent out a letter to agencies about it.
From the ATF FAQ...
- after July 12, 2016, CLEO certification is no longer required but applicants must send a copy of the application to make or transfer NFA firearms to their chief law enforcement officer notifying them of the application.
From the back of one of the new Form 1's...
Information for the Chief Law Enforcement Officer
This form provides notification of the applicant's intent to make and register a National Firearms Act (NFA) firearm. No action on your part is required. However, should you
have information that may disqualify this person from making or possessing a firearm, please contact the NFA Branch at (304) 616-4500 or
[email protected]. A "Yes" answer to
items 11.a through 11.h or 13.b or 13.c could disqualify a person from acquiring or possessing a firearm. Also, ATF will not approve an application if the making or possession of
the firearm is in violation of State or local law.