I emailed Henry Durrheim at riflepermits.com in regards to this issue and here is his reply:
Hi Jerome
We don’t have any issues currently with the SA Police, they still do accept old 4457 forms, we did however had a problem last year when the SA Police at the airport refused to issue permits as they referred to the expiry date on the CBP4457 customs form and informed the client that the form had expired, we then enquired with US customs and this was the feedback from US customs:
Recently you requested personal assistance from our on-line support center. Below is a summary of your request and our response.
If this issue is not resolved to your satisfaction, you may reopen it within the next 7 days.
Thank you for allowing us to be of service to you.
Subject
Form 4457 has an expiration date of 2/29/2016 and we are told will not be accept...
Discussion Thread
Response Via Email (PIO Butler)
12/16/2015 08:17 AM
Thank you for contacting the U.S. Customs and Border Protection (CBP) INFO Center.
Although this form is widely accepted in other countries, the purpose of CBP Form 4457 is to prove the item was in the U.S. prior to your travels, not proof of ownership to other countries. As long as the Certificate of Registration is for the same equipment, it can be used more than once. The description of the item and serial number must match. The expiration and subsequent replacement of the form does not negate the validity of the registration. Please check with the South African embassy to see what alternative documents they will accept as proof of ownership in the event the form is not accepted. The expiration is just the date that triggers a review of the form by the Office of Management and Budget. These types of forms continue to be valid until they are replaced by a new form.
If you have any other questions or concerns, please feel free to call our toll-free number 877-CBP-5511 (877-227-5511). From outside the United States, please call 202-325-8000 - you may incur charges from your telephone service provider for this call. Our service hours are Monday through Friday from 9 a.m.-4 p.m. Eastern Time. We are closed on all U.S. federal holidays.
We hope our answers ease your entry into the United States. Please understand these answers are informational only, The CBP officer who speaks with you upon arrival determines the admissibility of goods and visitors.
Thank you again for contacting the CBP INFO Center.
Sincerely,
CBP INFO Center
Kind regards,
Henry